Enable port inside panel bindings.

Fixes warnings generated by `make qcom-apq8064-asus-nexus7-flo.dtb` as:
arch/arm/boot/dts/qcom-apq8064-asus-nexus7-flo.dt.yaml: panel@0: 'port' does not match any of the regexes: 'pinctrl-[0-9]+'
	From schema: Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.yaml
Signed-off-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211224195354.78362-1-david@ixit.cz