drivers/interrupt_controller: stm32: Complete driver factorization
drivers/interrupt_controller: stm32: Complete driver factorization

Complete code factorization in stm32 exti drivers.


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

ldts/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,explora26/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,Vudentz/zephyr,explora26/zephyr,explora26/zephyr,nashif/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,galak/zephyr,Vudentz/zephyr,galak/zephyr,nashif/zephyr,finikorg/zephyr,finikorg/zephyr,ldts/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,galak/zephyr,nashif/zephyr,explora26/zephyr,finikorg/zephyr,explora26/zephyr,Vudentz/zephyr,ldts/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr