boards/stm32f4discovery: fix broken links
boards/stm32f4discovery: fix broken links


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