boards: arm: pinetime: Add chosen display
boards: arm: pinetime: Add chosen display

commit 65f0c8641c736bf2f10b8f330fcfb5e1f44b5046
("boards/shields: add zephyr,display chosen property")
added a chosen display property to most of the boards.
This was missing for the pinetime board.

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

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