UPSTREAM: drm/edid: Set 8 bpc color depth for displays with "DFP 1.x compliant TMDS".

UPSTREAM: drm/edid: Set 8 bpc color depth for displays with "DFP 1.x compliant TMDS".

According to E-EDID spec 1.3, table 3.9, a digital video sink with the
"DFP 1.x compliant TMDS" bit set is "signal compatible with VESA DFP 1.x
TMDS CRGB, 1 pixel / clock, up to 8 bits / color MSB aligned".

For such displays, the DFP spec 1.0, section 3.10 "EDID support" says:

"If the DFP monitor only supports EDID 1.X (1.1, 1.2, etc.)
 without extensions, the host will make the following assumptions:

 1. 24-bit MSB-aligned RGB TFT
 2. DE polarity is active high
 3. H and V syncs are active high
 4. Established CRT timings will be used
 5. Dithering will not be enabled on the host"

So if we don't know the bit depth of the display from additional
colorimetry info we should assume 8 bpc / 24 bpp by default.

This patch adds info->bpc = 8 assignement for that case.

Change-Id: Ie7603f8bf19eeeb1cd1988b6a245ead5d2e52763
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Zheng Yang <zhengyang@rock-chips.com>
(cherry picked from commit 210a021dab639694600450c14b877bf3e3240adc)