dt-bindings: display: ltk050h3146w: add port property

dt-bindings: display: ltk050h3146w: add port property

The panel can be connected to via graph nodes, so allow the port property.

This fixes dtc checker warnings like:
>> arch/arm64/boot/dts/rockchip/rk3588-tiger-haikou-haikou-video-demo.dtb: panel@0 (leadtek,ltk050h3148w): 'port' does not match any of the regexes: 'pinctrl-[0-9]+'
    from schema $id: http://devicetree.org/schemas/display/panel/leadtek,ltk050h3146w.yaml#
   arch/arm64/boot/dts/rockchip/rk3588-tiger-haikou-haikou-video-demo.dtb: /edp@fdec0000: failed to match any schema with compatible: ['rockchip,rk3588-edp']

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202504300218.VDqQqGTT-lkp@intel.com/
Signed-off-by: Heiko Stuebner <heiko.stuebner@cherry.de>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250430082850.244199-2-heiko@sntech.de
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>