soc: stm32f407xg: finish SOC renaming
soc: stm32f407xg: finish SOC renaming

Commit 599149dfb831 ("soc: stm32f407xg: rename SOC config flag") renamed
SOC_STM32F407XX to SOC_STM32F407XG but the text of the option should be
changed as well to reflect this restriction in scope.

Change-Id: Id03529452f5ec7d7ffee214b152c4aa555e1208a
Signed-off-by: Florian Vaussard <ef1e2bd37ca89620283a38ee0519838a257cab3b@heig-vd.ch>

holtmann/zephyr,explora26/zephyr,kraj/zephyr,Vudentz/zephyr,finikorg/zephyr,zephyriot/zephyr,kraj/zephyr,Vudentz/zephyr,rsalveti/zephyr,nashif/zephyr,explora26/zephyr,fbsder/zephyr,Vudentz/zephyr,rsalveti/zephyr,explora26/zephyr,punitvara/zephyr,Vudentz/zephyr,fbsder/zephyr,ldts/zephyr,explora26/zephyr,galak/zephyr,rsalveti/zephyr,mbolivar/zephyr,punitvara/zephyr,pklazy/zephyr,fractalclone/zephyr-riscv,zephyriot/zephyr,Vudentz/zephyr,fbsder/zephyr,fbsder/zephyr,runchip/zephyr-cc3220,ldts/zephyr,aceofall/zephyr-iotos,nashif/zephyr,galak/zephyr,galak/zephyr,mbolivar/zephyr,mbolivar/zephyr,kraj/zephyr,mbolivar/zephyr,ldts/zephyr,pklazy/zephyr,rsalveti/zephyr,holtmann/zephyr,zephyriot/zephyr,holtmann/zephyr,kraj/zephyr,punitvara/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,runchip/zephyr-cc3220,galak/zephyr,zephyrproject-rtos/zephyr,punitvara/zephyr,GiulianoFranchetto/zephyr,pklazy/zephyr,sharronliu/zephyr,zephyrproject-rtos/zephyr,holtmann/zephyr,fractalclone/zephyr-riscv,runchip/zephyr-cc3220,bigdinotech/zephyr,nashif/zephyr,Vudentz/zephyr,finikorg/zephyr,fbsder/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,punitvara/zephyr,fractalclone/zephyr-riscv,bigdinotech/zephyr,finikorg/zephyr,sharronliu/zephyr,finikorg/zephyr,aceofall/zephyr-iotos,pklazy/zephyr,sharronliu/zephyr,runchip/zephyr-cc3220,finikorg/zephyr,kraj/zephyr,ldts/zephyr,explora26/zephyr,bigdinotech/zephyr,pklazy/zephyr,zephyrproject-rtos/zephyr,fractalclone/zephyr-riscv,GiulianoFranchetto/zephyr,bigdinotech/zephyr,aceofall/zephyr-iotos,bigdinotech/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,zephyriot/zephyr,rsalveti/zephyr,mbolivar/zephyr,runchip/zephyr-cc3220,holtmann/zephyr,zephyriot/zephyr,GiulianoFranchetto/zephyr,sharronliu/zephyr,sharronliu/zephyr,fractalclone/zephyr-riscv,aceofall/zephyr-iotos,aceofall/zephyr-iotos,galak/zephyr