cpu/stm32l1: uart: make sure 'dev' is != NULL to avoid nullPointer errors
cpu/stm32l1: uart: make sure 'dev' is != NULL to avoid nullPointer errors

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