saul: add user button for samr21-xpro
saul: add user button for samr21-xpro

alignan/RIOT,basilfx/RIOT,Hyungsin/RIOT-OS,avmelnikoff/RIOT,TobiasFredersdorf/RIOT,ks156/RIOT,wentaoshang/RIOT,ant9000/RIOT,x3ro/RIOT,zhuoshuguo/RIOT,shady33/RIOT,FrancescoErmini/RIOT,MohmadAyman/RIOT,yogo1212/RIOT,dailab/RIOT,josephnoir/RIOT,jfischer-phytec-iot/RIOT,BytesGalore/RIOT,rousselk/RIOT,zhuoshuguo/RIOT,beurdouche/RIOT,backenklee/RIOT,mfrey/RIOT,rakendrathapa/RIOT,plushvoxel/RIOT,aeneby/RIOT,asanka-code/RIOT,ant9000/RIOT,RIOT-OS/RIOT,dkm/RIOT,kbumsik/RIOT,OlegHahm/RIOT,kerneltask/RIOT,gebart/RIOT,OlegHahm/RIOT,biboc/RIOT,dkm/RIOT,rousselk/RIOT,thomaseichinger/RIOT,d00616/RIOT,kaleb-himes/RIOT,tfar/RIOT,miri64/RIOT,kaspar030/RIOT,altairpearl/RIOT,binarylemon/RIOT,rousselk/RIOT,katezilla/RIOT,binarylemon/RIOT,kerneltask/RIOT,jbeyerstedt/RIOT-OTA-update,Ell-i/RIOT,authmillenon/RIOT,lazytech-org/RIOT,Yonezawa-T2/RIOT,jbeyerstedt/RIOT-OTA-update,kb2ma/RIOT,authmillenon/RIOT,BytesGalore/RIOT,thomaseichinger/RIOT,wentaoshang/RIOT,LudwigKnuepfer/RIOT,Josar/RIOT,rakendrathapa/RIOT,kaspar030/RIOT,neiljay/RIOT,toonst/RIOT,LudwigKnuepfer/RIOT,A-Paul/RIOT,kbumsik/RIOT,TobiasFredersdorf/RIOT,mtausig/RIOT,adrianghc/RIOT,mtausig/RIOT,hamilton-mote/RIOT-OS,kaspar030/RIOT,rfuentess/RIOT,dkm/RIOT,rfuentess/RIOT,Ell-i/RIOT,rfuentess/RIOT,LudwigOrtmann/RIOT,beurdouche/RIOT,syin2/RIOT,kaspar030/RIOT,avmelnikoff/RIOT,A-Paul/RIOT,Yonezawa-T2/RIOT,alignan/RIOT,Hyungsin/RIOT-OS,immesys/RiSyn,syin2/RIOT,lazytech-org/RIOT,malosek/RIOT,basilfx/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,basilfx/RIOT,ant9000/RIOT,kaleb-himes/RIOT,adjih/RIOT,dkm/RIOT,josephnoir/RIOT,FrancescoErmini/RIOT,jbeyerstedt/RIOT-OTA-update,katezilla/RIOT,A-Paul/RIOT,RIOT-OS/RIOT,Yonezawa-T2/RIOT,mtausig/RIOT,kbumsik/RIOT,kerneltask/RIOT,RIOT-OS/RIOT,adrianghc/RIOT,x3ro/RIOT,rakendrathapa/RIOT,LudwigOrtmann/RIOT,MohmadAyman/RIOT,roberthartung/RIOT,biboc/RIOT,Ell-i/RIOT,binarylemon/RIOT,smlng/RIOT,BytesGalore/RIOT,jasonatran/RIOT,cladmi/RIOT,jasonatran/RIOT,TobiasFredersdorf/RIOT,kb2ma/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,kaleb-himes/RIOT,gebart/RIOT,brettswann/RIOT,dailab/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,jremmert-phytec-iot/RIOT,mtausig/RIOT,jremmert-phytec-iot/RIOT,asanka-code/RIOT,mtausig/RIOT,malosek/RIOT,FrancescoErmini/RIOT,plushvoxel/RIOT,neiljay/RIOT,shady33/RIOT,neumodisch/RIOT,basilfx/RIOT,brettswann/RIOT,BytesGalore/RIOT,hamilton-mote/RIOT-OS,authmillenon/RIOT,biboc/RIOT,avmelnikoff/RIOT,d00616/RIOT,neiljay/RIOT,kbumsik/RIOT,cladmi/RIOT,toonst/RIOT,binarylemon/RIOT,alignan/RIOT,adrianghc/RIOT,shady33/RIOT,backenklee/RIOT,kaspar030/RIOT,syin2/RIOT,cladmi/RIOT,kaleb-himes/RIOT,jfischer-phytec-iot/RIOT,beurdouche/RIOT,brettswann/RIOT,adrianghc/RIOT,Hyungsin/RIOT-OS,FrancescoErmini/RIOT,Yonezawa-T2/RIOT,TobiasFredersdorf/RIOT,d00616/RIOT,Yonezawa-T2/RIOT,LudwigKnuepfer/RIOT,toonst/RIOT,backenklee/RIOT,zhuoshuguo/RIOT,plushvoxel/RIOT,brettswann/RIOT,adjih/RIOT,smlng/RIOT,avmelnikoff/RIOT,rajma996/RIOT,jbeyerstedt/RIOT-OTA-update,adjih/RIOT,thomaseichinger/RIOT,altairpearl/RIOT,Ell-i/RIOT,roberthartung/RIOT,dailab/RIOT,Ell-i/RIOT,lazytech-org/RIOT,gautric/RIOT,kYc0o/RIOT,FrancescoErmini/RIOT,gautric/RIOT,x3ro/RIOT,Josar/RIOT,malosek/RIOT,neumodisch/RIOT,beurdouche/RIOT,binarylemon/RIOT,jasonatran/RIOT,jremmert-phytec-iot/RIOT,dailab/RIOT,rousselk/RIOT,katezilla/RIOT,thomaseichinger/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,x3ro/RIOT,OTAkeys/RIOT,alignan/RIOT,kb2ma/RIOT,gautric/RIOT,rajma996/RIOT,mfrey/RIOT,adrianghc/RIOT,neiljay/RIOT,rousselk/RIOT,mfrey/RIOT,miri64/RIOT,josephnoir/RIOT,neumodisch/RIOT,tfar/RIOT,syin2/RIOT,adjih/RIOT,ant9000/RIOT,yogo1212/RIOT,LudwigKnuepfer/RIOT,yogo1212/RIOT,authmillenon/RIOT,zhuoshuguo/RIOT,d00616/RIOT,OlegHahm/RIOT,tfar/RIOT,neumodisch/RIOT,kYc0o/RIOT,attdona/RIOT,kaleb-himes/RIOT,roberthartung/RIOT,ks156/RIOT,plushvoxel/RIOT,jfischer-phytec-iot/RIOT,asanka-code/RIOT,MohmadAyman/RIOT,hamilton-mote/RIOT-OS,Josar/RIOT,Josar/RIOT,BytesGalore/RIOT,d00616/RIOT,tfar/RIOT,miri64/RIOT,toonst/RIOT,gebart/RIOT,attdona/RIOT,rakendrathapa/RIOT,wentaoshang/RIOT,syin2/RIOT,aeneby/RIOT,rajma996/RIOT,gautric/RIOT,rfuentess/RIOT,jfischer-phytec-iot/RIOT,lazytech-org/RIOT,altairpearl/RIOT,OTAkeys/RIOT,alignan/RIOT,rajma996/RIOT,ant9000/RIOT,neumodisch/RIOT,OlegHahm/RIOT,d00616/RIOT,rousselk/RIOT,cladmi/RIOT,Hyungsin/RIOT-OS,gautric/RIOT,altairpearl/RIOT,attdona/RIOT,miri64/RIOT,thomaseichinger/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,basilfx/RIOT,rfuentess/RIOT,A-Paul/RIOT,malosek/RIOT,smlng/RIOT,aeneby/RIOT,binarylemon/RIOT,A-Paul/RIOT,LudwigOrtmann/RIOT,roberthartung/RIOT,wentaoshang/RIOT,jremmert-phytec-iot/RIOT,OlegHahm/RIOT,LudwigOrtmann/RIOT,attdona/RIOT,jbeyerstedt/RIOT-OTA-update,dailab/RIOT,authmillenon/RIOT,josephnoir/RIOT,ks156/RIOT,roberthartung/RIOT,MohmadAyman/RIOT,dkm/RIOT,kb2ma/RIOT,kbumsik/RIOT,MohmadAyman/RIOT,malosek/RIOT,shady33/RIOT,attdona/RIOT,katezilla/RIOT,attdona/RIOT,plushvoxel/RIOT,ks156/RIOT,kerneltask/RIOT,LudwigOrtmann/RIOT,adjih/RIOT,brettswann/RIOT,shady33/RIOT,immesys/RiSyn,zhuoshuguo/RIOT,RIOT-OS/RIOT,wentaoshang/RIOT,altairpearl/RIOT,rajma996/RIOT,smlng/RIOT,rajma996/RIOT,josephnoir/RIOT,toonst/RIOT,immesys/RiSyn,brettswann/RIOT,katezilla/RIOT,neiljay/RIOT,yogo1212/RIOT,hamilton-mote/RIOT-OS,kb2ma/RIOT,kerneltask/RIOT,jasonatran/RIOT,gebart/RIOT,smlng/RIOT,neumodisch/RIOT,rakendrathapa/RIOT,mfrey/RIOT,asanka-code/RIOT,shady33/RIOT,kYc0o/RIOT,immesys/RiSyn,LudwigKnuepfer/RIOT,authmillenon/RIOT,jremmert-phytec-iot/RIOT,cladmi/RIOT,backenklee/RIOT,yogo1212/RIOT,OTAkeys/RIOT,altairpearl/RIOT,kYc0o/RIOT,immesys/RiSyn,asanka-code/RIOT,jasonatran/RIOT,biboc/RIOT,malosek/RIOT,LudwigOrtmann/RIOT,lazytech-org/RIOT,beurdouche/RIOT,FrancescoErmini/RIOT,rakendrathapa/RIOT,miri64/RIOT,jfischer-phytec-iot/RIOT,OTAkeys/RIOT,MohmadAyman/RIOT,mfrey/RIOT,biboc/RIOT,wentaoshang/RIOT,TobiasFredersdorf/RIOT,OTAkeys/RIOT,asanka-code/RIOT,immesys/RiSyn,jremmert-phytec-iot/RIOT,yogo1212/RIOT,Josar/RIOT,gebart/RIOT,aeneby/RIOT,aeneby/RIOT,hamilton-mote/RIOT-OS,tfar/RIOT,x3ro/RIOT,zhuoshuguo/RIOT,ks156/RIOT,backenklee/RIOT,avmelnikoff/RIOT,Yonezawa-T2/RIOT,Hyungsin/RIOT-OS,foss-for-synopsys-dwc-arc-processors/RIOT