cpu/stm32: GPIO ports definition fix
cpu/stm32: GPIO ports definition fix

The available GPIO ports may also differ within a family. Therefore, the vendor definitions GPIO* are used instad of CPU_FAM_STM definitions to determine which ports are available for a certain MCU.
OlegHahm/RIOT,kYc0o/RIOT,OTAkeys/RIOT,ant9000/RIOT,ant9000/RIOT,miri64/RIOT,OTAkeys/RIOT,jasonatran/RIOT,miri64/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,OTAkeys/RIOT,kaspar030/RIOT,kaspar030/RIOT,jasonatran/RIOT,OTAkeys/RIOT,authmillenon/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,miri64/RIOT,kYc0o/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,OlegHahm/RIOT,kaspar030/RIOT,miri64/RIOT,authmillenon/RIOT,authmillenon/RIOT,jasonatran/RIOT,kaspar030/RIOT,authmillenon/RIOT,jasonatran/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,ant9000/RIOT,kaspar030/RIOT,kYc0o/RIOT,ant9000/RIOT,authmillenon/RIOT,miri64/RIOT,ant9000/RIOT,kYc0o/RIOT