dt-bindings: Add Sharp LQ123P1JX31 panel binding

The Sharp LQ123P1JX31 is an 12.3" 2400x1600 TFT-LCD panel
connected using eDP interfaces.
Signed-off-by: Yakir Yang <ykk@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Documentation/devicetree/bindings/display/panel/sharp,lq123p1jx31.txt

+Sharp 12.3" (2400x1600 pixels) TFT LCD panel
+
+Required properties:
+- compatible: should be "sharp,lq123p1jx31"
+
+This binding is compatible with the simple-panel binding, which is specified
+in simple-panel.txt in this directory.