drivers/gpio: stm32 fix gpio device init prio
drivers/gpio: stm32 fix gpio device init prio

STM32 GPIO device initialization priority was set to
CONFIG_KERNEL_INIT_PRIORITY_DEFAULT
Following introduction of __ZEPHYR_SUPERVISOR__ macro (#6835),
drivers intialization order have been reordered which blocks
some use cases now.
Increase GPIO init priority to get it initialized before SPI
and avoid a deadlock.

Fixes #7663


Signed-off-by: Erwan Gouriou <de4d967452b83bb0e37525652734e7d9163b6a4c@linaro.org>

punitvara/zephyr,finikorg/zephyr,mbolivar/zephyr,kraj/zephyr,punitvara/zephyr,zephyriot/zephyr,nashif/zephyr,Vudentz/zephyr,finikorg/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,mbolivar/zephyr,explora26/zephyr,punitvara/zephyr,explora26/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,zephyriot/zephyr,Vudentz/zephyr,explora26/zephyr,punitvara/zephyr,zephyriot/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,punitvara/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,finikorg/zephyr,mbolivar/zephyr,nashif/zephyr,mbolivar/zephyr,Vudentz/zephyr,Vudentz/zephyr,zephyriot/zephyr,finikorg/zephyr,finikorg/zephyr,ldts/zephyr,mbolivar/zephyr,zephyriot/zephyr,GiulianoFranchetto/zephyr,kraj/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,ldts/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,kraj/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,kraj/zephyr,explora26/zephyr,nashif/zephyr,kraj/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,ldts/zephyr,explora26/zephyr