drivers: pinctrl: rcar: Rework pin configuration
drivers: pinctrl: rcar: Rework pin configuration

Rework pin configuration to meet documented procedures.
3 procedures are covered here:
  - GPIO -> Peripheral (+select peripheral function)
  - Peripheral -> GPIO
  - Change from Peripheral function 1 -> Peripheral function 2

Signed-off-by: Aymeric Aillet <50ecb97e8539231bfe69207a233bb1580c5def34@iot.bzh>

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