dts: arm: st: l4: add include for LTDC bindings
dts: arm: st: l4: add include for LTDC bindings

Add LTDC bindings include so boards don't have to include it

Signed-off-by: Tomislav Milkovic <2161fd1c3ce8f78557aeb421b2032be96a827bf6@gmail.com>

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