Replace additionalProperties with unevaluatedProperties because it ref to
panel-common.yaml.

Remove properties (backlight, enable-gpios and power-supply), which defined
in panel-common.yaml.

Fix below warning:
arch/arm64/boot/dts/freescale/imx8mp-evk-mx8-dlvds-lcd1.dtb: panel-lvds: 'panel-timing' does not match any of the regexes: 'pinctrl-[0-9]+'
        from schema $id: http://devicetree.org/schemas/display/panel/panel-simple-lvds-dual-ports.yaml#Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240812193626.3826250-1-Frank.Li@nxp.comSigned-off-by: Rob Herring (Arm) <robh@kernel.org>