cpu/cortexm: raised ISR stack size to safer value
cpu/cortexm: raised ISR stack size to safer value

256 Byte were not enough for some boards (not sure why, yet).
So go back to 512 byte as a save (and known working value).

A-Paul/RIOT,alex1818/RIOT,lazytech-org/RIOT,chris-wood/RIOT,Josar/RIOT,dkm/RIOT,haoyangyu/RIOT,sumanpanchal/RIOT,automote/RIOT,abkam07/RIOT,backenklee/RIOT,changbiao/RIOT,adjih/RIOT,luciotorre/RIOT,immesys/RiSyn,sumanpanchal/RIOT,zhuoshuguo/RIOT,Lexandro92/RIOT-CoAP,plushvoxel/RIOT,centurysys/RIOT,EmuxEvans/RIOT,syin2/RIOT,neiljay/RIOT,katezilla/RIOT,Osblouf/RIOT,LudwigKnuepfer/RIOT,kYc0o/RIOT,roberthartung/RIOT,dkm/RIOT,alex1818/RIOT,l3nko/RIOT,rfswarm/RIOT,Yonezawa-T2/RIOT,luciotorre/RIOT,roberthartung/RIOT,LudwigOrtmann/RIOT,kbumsik/RIOT,jferreir/RIOT,Darredevil/RIOT,toonst/RIOT,abkam07/RIOT,Lexandro92/RIOT-CoAP,jfischer-phytec-iot/RIOT,authmillenon/RIOT,khhhh/RIOT,immesys/RiSyn,chris-wood/RIOT,mtausig/RIOT,herrfz/RIOT,kaleb-himes/RIOT,benoit-canet/RIOT,ThanhVic/RIOT,kushalsingh007/RIOT,alex1818/RIOT,bartfaizoltan/RIOT,neumodisch/RIOT,neumodisch/RIOT,wentaoshang/RIOT,neumodisch/RIOT,Darredevil/RIOT,gautric/RIOT,MonsterCode8000/RIOT,neumodisch/RIOT,DipSwitch/RIOT,luciotorre/RIOT,Darredevil/RIOT,Ell-i/RIOT,asanka-code/RIOT,kushalsingh007/RIOT,MarkXYang/RIOT,kaspar030/RIOT,ThanhVic/RIOT,Osblouf/RIOT,stevenj/RIOT,RIOT-OS/RIOT,MarkXYang/RIOT,RIOT-OS/RIOT,wentaoshang/RIOT,plushvoxel/RIOT,avmelnikoff/RIOT,benoit-canet/RIOT,msolters/RIOT,ximus/RIOT,OlegHahm/RIOT,basilfx/RIOT,ant9000/RIOT,benoit-canet/RIOT,DipSwitch/RIOT,benoit-canet/RIOT,gebart/RIOT,automote/RIOT,plushvoxel/RIOT,avmelnikoff/RIOT,latsku/RIOT,jfischer-phytec-iot/RIOT,basilfx/RIOT,herrfz/RIOT,Ell-i/RIOT,attdona/RIOT,jferreir/RIOT,kushalsingh007/RIOT,mziegert/RIOT,OTAkeys/RIOT,adjih/RIOT,altairpearl/RIOT,RubikonAlpha/RIOT,kushalsingh007/RIOT,x3ro/RIOT,beurdouche/RIOT,robixnai/RIOT,kbumsik/RIOT,jferreir/RIOT,kaspar030/RIOT,changbiao/RIOT,jfischer-phytec-iot/RIOT,kerneltask/RIOT,watr-li/RIOT,jfischer-phytec-iot/RIOT,yogo1212/RIOT,bartfaizoltan/RIOT,watr-li/RIOT,MonsterCode8000/RIOT,rakendrathapa/RIOT,daniel-k/RIOT,dhruvvyas90/RIOT,kaleb-himes/RIOT,binarylemon/RIOT,beurdouche/RIOT,jfischer-phytec-iot/RIOT,centurysys/RIOT,jbeyerstedt/RIOT-OTA-update,RBartz/RIOT,herrfz/RIOT,josephnoir/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,biboc/RIOT,smlng/RIOT,tfar/RIOT,Yonezawa-T2/RIOT,rfswarm/RIOT,phiros/RIOT,msolters/RIOT,malosek/RIOT,luciotorre/RIOT,asanka-code/RIOT,MonsterCode8000/RIOT,ximus/RIOT,openkosmosorg/RIOT,altairpearl/RIOT,malosek/RIOT,beurdouche/RIOT,lebrush/RIOT,MarkXYang/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,rfswarm/RIOT,Hyungsin/RIOT-OS,roberthartung/RIOT,yogo1212/RIOT,zhuoshuguo/RIOT,phiros/RIOT,zhuoshuguo/RIOT,josephnoir/RIOT,Josar/RIOT,syin2/RIOT,Osblouf/RIOT,kerneltask/RIOT,kushalsingh007/RIOT,msolters/RIOT,Lexandro92/RIOT-CoAP,altairpearl/RIOT,authmillenon/RIOT,thomaseichinger/RIOT,marcosalm/RIOT,rajma996/RIOT,basilfx/RIOT,d00616/RIOT,chris-wood/RIOT,ntrtrung/RIOT,bartfaizoltan/RIOT,adrianghc/RIOT,alignan/RIOT,watr-li/RIOT,wentaoshang/RIOT,biboc/RIOT,latsku/RIOT,aeneby/RIOT,abp719/RIOT,BytesGalore/RIOT,bartfaizoltan/RIOT,mfrey/RIOT,plushvoxel/RIOT,kerneltask/RIOT,automote/RIOT,TobiasFredersdorf/RIOT,dailab/RIOT,thiagohd/RIOT,sgso/RIOT,sgso/RIOT,stevenj/RIOT,neumodisch/RIOT,dhruvvyas90/RIOT,patkan/RIOT,FrancescoErmini/RIOT,jferreir/RIOT,haoyangyu/RIOT,rajma996/RIOT,A-Paul/RIOT,MonsterCode8000/RIOT,openkosmosorg/RIOT,thomaseichinger/RIOT,FrancescoErmini/RIOT,koenning/RIOT,l3nko/RIOT,gautric/RIOT,JensErdmann/RIOT,gautric/RIOT,d00616/RIOT,Darredevil/RIOT,Osblouf/RIOT,aeneby/RIOT,gebart/RIOT,RIOT-OS/RIOT,asanka-code/RIOT,cladmi/RIOT,katezilla/RIOT,marcosalm/RIOT,herrfz/RIOT,gautric/RIOT,tdautc19841202/RIOT,tdautc19841202/RIOT,lebrush/RIOT,adjih/RIOT,PSHIVANI/Riot-Code,kaspar030/RIOT,roberthartung/RIOT,khhhh/RIOT,shady33/RIOT,alignan/RIOT,abkam07/RIOT,koenning/RIOT,backenklee/RIOT,jremmert-phytec-iot/RIOT,RBartz/RIOT,patkan/RIOT,herrfz/RIOT,rakendrathapa/RIOT,ks156/RIOT,EmuxEvans/RIOT,LudwigKnuepfer/RIOT,stevenj/RIOT,neiljay/RIOT,OTAkeys/RIOT,robixnai/RIOT,openkosmosorg/RIOT,Osblouf/RIOT,abp719/RIOT,daniel-k/RIOT,rousselk/RIOT,robixnai/RIOT,ximus/RIOT,altairpearl/RIOT,automote/RIOT,thiagohd/RIOT,ks156/RIOT,dailab/RIOT,Ell-i/RIOT,Yonezawa-T2/RIOT,phiros/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,OlegHahm/RIOT,A-Paul/RIOT,patkan/RIOT,hamilton-mote/RIOT-OS,DipSwitch/RIOT,authmillenon/RIOT,watr-li/RIOT,jremmert-phytec-iot/RIOT,attdona/RIOT,herrfz/RIOT,dhruvvyas90/RIOT,PSHIVANI/Riot-Code,malosek/RIOT,EmuxEvans/RIOT,MohmadAyman/RIOT,sgso/RIOT,sgso/RIOT,beurdouche/RIOT,adjih/RIOT,zhuoshuguo/RIOT,Hyungsin/RIOT-OS,khhhh/RIOT,thomaseichinger/RIOT,JensErdmann/RIOT,kbumsik/RIOT,PSHIVANI/Riot-Code,jasonatran/RIOT,katezilla/RIOT,ThanhVic/RIOT,Hyungsin/RIOT-OS,attdona/RIOT,rousselk/RIOT,mziegert/RIOT,RIOT-OS/RIOT,brettswann/RIOT,OTAkeys/RIOT,LudwigOrtmann/RIOT,jbeyerstedt/RIOT-OTA-update,alex1818/RIOT,koenning/RIOT,TobiasFredersdorf/RIOT,kYc0o/RIOT,syin2/RIOT,patkan/RIOT,miri64/RIOT,attdona/RIOT,thomaseichinger/RIOT,alignan/RIOT,brettswann/RIOT,changbiao/RIOT,rousselk/RIOT,kYc0o/RIOT,tfar/RIOT,hamilton-mote/RIOT-OS,ximus/RIOT,Hyungsin/RIOT-OS,thiagohd/RIOT,malosek/RIOT,BytesGalore/RIOT,jasonatran/RIOT,adrianghc/RIOT,haoyangyu/RIOT,hamilton-mote/RIOT-OS,kaspar030/RIOT,malosek/RIOT,aeneby/RIOT,mtausig/RIOT,yogo1212/RIOT,avmelnikoff/RIOT,cladmi/RIOT,tdautc19841202/RIOT,gbarnett/RIOT,latsku/RIOT,rfuentess/RIOT,khhhh/RIOT,miri64/RIOT,Darredevil/RIOT,LudwigOrtmann/RIOT,rajma996/RIOT,kYc0o/RIOT,kerneltask/RIOT,Yonezawa-T2/RIOT,haoyangyu/RIOT,daniel-k/RIOT,phiros/RIOT,dailab/RIOT,immesys/RiSyn,FrancescoErmini/RIOT,koenning/RIOT,toonst/RIOT,basilfx/RIOT,TobiasFredersdorf/RIOT,kb2ma/RIOT,haoyangyu/RIOT,haoyangyu/RIOT,LudwigOrtmann/RIOT,cladmi/RIOT,kerneltask/RIOT,jremmert-phytec-iot/RIOT,x3ro/RIOT,backenklee/RIOT,jremmert-phytec-iot/RIOT,bartfaizoltan/RIOT,altairpearl/RIOT,lebrush/RIOT,authmillenon/RIOT,wentaoshang/RIOT,aeneby/RIOT,plushvoxel/RIOT,LudwigOrtmann/RIOT,kb2ma/RIOT,sumanpanchal/RIOT,phiros/RIOT,JensErdmann/RIOT,cladmi/RIOT,dkm/RIOT,robixnai/RIOT,Lexandro92/RIOT-CoAP,MohmadAyman/RIOT,wentaoshang/RIOT,cladmi/RIOT,sumanpanchal/RIOT,abp719/RIOT,automote/RIOT,centurysys/RIOT,chris-wood/RIOT,thiagohd/RIOT,mtausig/RIOT,mziegert/RIOT,FrancescoErmini/RIOT,Josar/RIOT,shady33/RIOT,ant9000/RIOT,yogo1212/RIOT,neumodisch/RIOT,khhhh/RIOT,kbumsik/RIOT,dhruvvyas90/RIOT,arvindpdmn/RIOT,aeneby/RIOT,adrianghc/RIOT,latsku/RIOT,DipSwitch/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,jbeyerstedt/RIOT-OTA-update,MarkXYang/RIOT,lazytech-org/RIOT,ant9000/RIOT,smlng/RIOT,x3ro/RIOT,RBartz/RIOT,backenklee/RIOT,MohmadAyman/RIOT,kaleb-himes/RIOT,Lexandro92/RIOT-CoAP,jbeyerstedt/RIOT-OTA-update,watr-li/RIOT,RubikonAlpha/RIOT,syin2/RIOT,smlng/RIOT,altairpearl/RIOT,backenklee/RIOT,arvindpdmn/RIOT,ntrtrung/RIOT,Ell-i/RIOT,josephnoir/RIOT,mfrey/RIOT,stevenj/RIOT,kushalsingh007/RIOT,watr-li/RIOT,openkosmosorg/RIOT,LudwigKnuepfer/RIOT,adrianghc/RIOT,RubikonAlpha/RIOT,patkan/RIOT,tdautc19841202/RIOT,josephnoir/RIOT,brettswann/RIOT,daniel-k/RIOT,mziegert/RIOT,jbeyerstedt/RIOT-OTA-update,rakendrathapa/RIOT,shady33/RIOT,A-Paul/RIOT,changbiao/RIOT,Hyungsin/RIOT-OS,attdona/RIOT,smlng/RIOT,openkosmosorg/RIOT,biboc/RIOT,BytesGalore/RIOT,ant9000/RIOT,malosek/RIOT,binarylemon/RIOT,BytesGalore/RIOT,abp719/RIOT,luciotorre/RIOT,OTAkeys/RIOT,centurysys/RIOT,MohmadAyman/RIOT,OlegHahm/RIOT,OlegHahm/RIOT,immesys/RiSyn,EmuxEvans/RIOT,jremmert-phytec-iot/RIOT,arvindpdmn/RIOT,rfswarm/RIOT,MohmadAyman/RIOT,x3ro/RIOT,benoit-canet/RIOT,abkam07/RIOT,daniel-k/RIOT,bartfaizoltan/RIOT,marcosalm/RIOT,adjih/RIOT,gbarnett/RIOT,miri64/RIOT,dhruvvyas90/RIOT,authmillenon/RIOT,katezilla/RIOT,yogo1212/RIOT,avmelnikoff/RIOT,abp719/RIOT,avmelnikoff/RIOT,PSHIVANI/Riot-Code,stevenj/RIOT,jasonatran/RIOT,d00616/RIOT,rfuentess/RIOT,arvindpdmn/RIOT,toonst/RIOT,tfar/RIOT,FrancescoErmini/RIOT,RubikonAlpha/RIOT,miri64/RIOT,d00616/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,MonsterCode8000/RIOT,d00616/RIOT,jferreir/RIOT,shady33/RIOT,gebart/RIOT,beurdouche/RIOT,ks156/RIOT,DipSwitch/RIOT,JensErdmann/RIOT,patkan/RIOT,mfrey/RIOT,basilfx/RIOT,sgso/RIOT,arvindpdmn/RIOT,tfar/RIOT,biboc/RIOT,rakendrathapa/RIOT,dailab/RIOT,rfswarm/RIOT,binarylemon/RIOT,hamilton-mote/RIOT-OS,mfrey/RIOT,brettswann/RIOT,syin2/RIOT,gbarnett/RIOT,LudwigKnuepfer/RIOT,tfar/RIOT,phiros/RIOT,chris-wood/RIOT,lebrush/RIOT,ThanhVic/RIOT,Yonezawa-T2/RIOT,ximus/RIOT,marcosalm/RIOT,gbarnett/RIOT,thomaseichinger/RIOT,d00616/RIOT,lebrush/RIOT,dailab/RIOT,x3ro/RIOT,gautric/RIOT,ThanhVic/RIOT,dhruvvyas90/RIOT,binarylemon/RIOT,luciotorre/RIOT,marcosalm/RIOT,gebart/RIOT,DipSwitch/RIOT,robixnai/RIOT,neiljay/RIOT,l3nko/RIOT,Lexandro92/RIOT-CoAP,miri64/RIOT,l3nko/RIOT,benoit-canet/RIOT,msolters/RIOT,tdautc19841202/RIOT,biboc/RIOT,mtausig/RIOT,TobiasFredersdorf/RIOT,rfswarm/RIOT,centurysys/RIOT,neiljay/RIOT,JensErdmann/RIOT,smlng/RIOT,lazytech-org/RIOT,automote/RIOT,gbarnett/RIOT,ximus/RIOT,EmuxEvans/RIOT,rakendrathapa/RIOT,asanka-code/RIOT,abkam07/RIOT,alignan/RIOT,thiagohd/RIOT,marcosalm/RIOT,rajma996/RIOT,rajma996/RIOT,ant9000/RIOT,rfuentess/RIOT,lebrush/RIOT,rousselk/RIOT,Ell-i/RIOT,OlegHahm/RIOT,dkm/RIOT,adrianghc/RIOT,katezilla/RIOT,l3nko/RIOT,ThanhVic/RIOT,wentaoshang/RIOT,BytesGalore/RIOT,sumanpanchal/RIOT,changbiao/RIOT,lazytech-org/RIOT,latsku/RIOT,kYc0o/RIOT,mfrey/RIOT,OTAkeys/RIOT,zhuoshuguo/RIOT,jasonatran/RIOT,MarkXYang/RIOT,MonsterCode8000/RIOT,alignan/RIOT,rajma996/RIOT,RBartz/RIOT,RIOT-OS/RIOT,ntrtrung/RIOT,roberthartung/RIOT,gbarnett/RIOT,Darredevil/RIOT,FrancescoErmini/RIOT,immesys/RiSyn,LudwigKnuepfer/RIOT,sgso/RIOT,ntrtrung/RIOT,shady33/RIOT,RubikonAlpha/RIOT,RubikonAlpha/RIOT,kb2ma/RIOT,LudwigOrtmann/RIOT,JensErdmann/RIOT,rousselk/RIOT,kaleb-himes/RIOT,asanka-code/RIOT,brettswann/RIOT,yogo1212/RIOT,brettswann/RIOT,binarylemon/RIOT,binarylemon/RIOT,chris-wood/RIOT,kb2ma/RIOT,abkam07/RIOT,jremmert-phytec-iot/RIOT,Josar/RIOT,RBartz/RIOT,MarkXYang/RIOT,josephnoir/RIOT,toonst/RIOT,ks156/RIOT,authmillenon/RIOT,A-Paul/RIOT,abp719/RIOT,jasonatran/RIOT,ntrtrung/RIOT,thiagohd/RIOT,ks156/RIOT,jferreir/RIOT,daniel-k/RIOT,openkosmosorg/RIOT,rfuentess/RIOT,rousselk/RIOT,MohmadAyman/RIOT,toonst/RIOT,changbiao/RIOT,dkm/RIOT,rakendrathapa/RIOT,khhhh/RIOT,Yonezawa-T2/RIOT,PSHIVANI/Riot-Code,Josar/RIOT,msolters/RIOT,hamilton-mote/RIOT-OS,TobiasFredersdorf/RIOT,PSHIVANI/Riot-Code,kb2ma/RIOT,alex1818/RIOT,arvindpdmn/RIOT,koenning/RIOT,immesys/RiSyn,alex1818/RIOT,Osblouf/RIOT,neiljay/RIOT,robixnai/RIOT,shady33/RIOT,stevenj/RIOT,zhuoshuguo/RIOT,kaspar030/RIOT,tdautc19841202/RIOT,koenning/RIOT,l3nko/RIOT,centurysys/RIOT,gebart/RIOT,sumanpanchal/RIOT,msolters/RIOT,latsku/RIOT,lazytech-org/RIOT,ntrtrung/RIOT,mziegert/RIOT,rfuentess/RIOT,kbumsik/RIOT,kaleb-himes/RIOT,attdona/RIOT,RBartz/RIOT,mziegert/RIOT,asanka-code/RIOT,EmuxEvans/RIOT,mtausig/RIOT