boards: arm: pinetime_devkit0: doc: Add unlock notice
boards: arm: pinetime_devkit0: doc: Add unlock notice

Add a note for newer PineTime watches that do not require unlocking

Signed-off-by: Casper Meijn <ef7830db5bfbf3536820c00105ab5734ef4609fc@meijn.net>

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