common/stm32: remove obsolete spi_divtable config
common/stm32: remove obsolete spi_divtable config

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