Add device tree bindings for the LCD Controller (LCDC) found in Renesas
SuperH SH-Mobile and ARM SH/R-Mobile SOCs.

Based on a plain text prototype by Laurent Pinchart.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/6d0a053502abd6555e9a6cbe055e1bdc3329999d.1694767208.git.geert+renesas@glider.be