gpio: implement pin_get_config in stm32 driver
gpio: implement pin_get_config in stm32 driver

This commit adds support for pin_get_config function in stm32 driver.

Signed-off-by: Michał Barnaś <77666125932addc6fc525b281b518fd8fd2203d8@semihalf.com>

galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr