drivers: uart: rcar: Fix typo in conf phase
drivers: uart: rcar: Fix typo in conf phase

Fix typo in configuration phase to prepare the driver
for incoming add of Interrupt driven uart mode.

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

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