stm32/spi: Add define for default CR2 settings
stm32/spi: Add define for default CR2 settings

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