Add the RGB666 9:9 format MEDIA_BUS_FMT_RGB666_2X9_BE, which is
supported by the SH-Mobile LCD Controller.
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/8b421cc391ac511c07cb1e243c1ba18bb95f7f98.1694767209.git.geert+renesas@glider.be