drm/omap: hdmi5: automatically choose limited/full range output

Currently the HDMI driver uses always limited range RGB output. This
patch improves the behavior by using limited range only if the output is
identified as a HDMI display, and VIC > 1.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190930103840.18970-7-tomi.valkeinen@ti.com