driver: wdt: npcx: correct the drawing of npcx watchdog module.
driver: wdt: npcx: correct the drawing of npcx watchdog module.

The source clock of the watchdog module is selected to the input of T0
timer, not output. Correct the drawing in case confusing the users.

Signed-off-by: Mulin Chao <6bbc5af053a1dfdc363be6857f30de4ac3bcbd16@nuvoton.com>

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