cpu: cortexm_common: fix compile warning
cpu: cortexm_common: fix compile warning

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