drivers: display: st7789v: add power management support
drivers: display: st7789v: add power management support

This adds sleep mode along with power managament control.

Signed-off-by: Albin Söderqvist <7e69b4e60f091dd6025a652c2758711b43995b0c@endian.se>

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