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>