i.MX6UL(L) uses "fsl,imx6sx-lcdif" as fallback compatible string,i'm not sure this is a good idea. In case i.MX6UL(L) is different from
but has only very lightweight DISPLAY power domain. Its DISPLAY
power domain is not supported by the binding / Linux kernel at
the moment. Since the current setup is working, let's remove the
power-domain from being required for that platform to fix the warning
printed by CHECK_DTBS=y.