OMAPDSS: HDMI4: Accept non-standard timings

The hdmi4 driver currently rejects any timing which is not from the CEA or VESA
standards. This leads hdmi rejecting any non-standard mode. A non standard
timing may not have a valid code corresponding to it. In such cases, the HDMI
spec suggests to set the code to 0.

Modify the driver to check if the timings fall within the range of the DISPC
TV overlay manager, and remove the check for an invalid code. Add a debug print
specifying the mode and code in hdmi_display_set_timing.

Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>