dt-bindings: display: Add Document for Rockchip Soc LVDS

dt-bindings: display: Add Document for Rockchip Soc LVDS

This patch add Document for Rockchip Soc RK3288 LVDS,
This based on the patches from Mark yao and Heiko Stuebner.

Signed-off-by: Mark yao <[email protected]>
Signed-off-by: Heiko Stuebner <[email protected]>
Signed-off-by: Sandy Huang <[email protected]>
Reviewed-by: Mark Yao <[email protected]>
Reviewed-by: Rob Herring <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]