drm/omap: Enable COLOR_ENCODING and COLOR_RANGE properties for planes

Adds support for COLOR_ENCODING and COLOR_RANGE properties to
omap_plane.c and dispc.c. The supported encodings and ranges are
presets are:

For COLOR_ENCODING:
- YCbCr BT.601 (default)
- YCbCr BT.709

For COLOR_RANGE:
- YCbCr limited range
- YCbCr full range (default)

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103080310.164453-6-tomi.valkeinen@ti.com