dts: arm: stm32g0: Add cpu0 label
dts: arm: stm32g0: Add cpu0 label

Add cpu0 label for cpu-idle-states later.

Signed-off-by: Yong Cong Sin <d1951b00420cc51c2da597170bb83d89fa46ae3b@gmail.com>

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