sys/can: fix broken links
sys/can: fix broken links

miri64/RIOT,kaspar030/RIOT,yogo1212/RIOT,RIOT-OS/RIOT,miri64/RIOT,kaspar030/RIOT,yogo1212/RIOT,jasonatran/RIOT,miri64/RIOT,ant9000/RIOT,kYc0o/RIOT,basilfx/RIOT,basilfx/RIOT,basilfx/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,yogo1212/RIOT,kaspar030/RIOT,kaspar030/RIOT,ant9000/RIOT,OTAkeys/RIOT,OlegHahm/RIOT,basilfx/RIOT,jasonatran/RIOT,authmillenon/RIOT,OTAkeys/RIOT,yogo1212/RIOT,authmillenon/RIOT,OlegHahm/RIOT,yogo1212/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,ant9000/RIOT,kaspar030/RIOT,OlegHahm/RIOT,kYc0o/RIOT,yogo1212/RIOT,authmillenon/RIOT,ant9000/RIOT,authmillenon/RIOT,miri64/RIOT,jasonatran/RIOT,OlegHahm/RIOT,jasonatran/RIOT,jasonatran/RIOT,miri64/RIOT,OTAkeys/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,OlegHahm/RIOT,OTAkeys/RIOT,OTAkeys/RIOT,basilfx/RIOT,authmillenon/RIOT,ant9000/RIOT,RIOT-OS/RIOT