drm/edid: Consider alternate cea timings to be the same VIC

drm/edid: Consider alternate cea timings to be the same VIC

CEA-861 specifies that the vertical front porch may vary by one or two
lines for specific VICs. Up to now we've only considered a mode to match
the VIC if it matched the shortest possible vertical front porch length
(as that is the variant we store in cea_modes[]). Let's allow our VIC
matching to work with the other timings variants as well so that that
we'll send out the correct VIC if the variant actually used isn't the
one with the shortest vertical front porch.

Cc: Shashank Sharma <shashank.sharma@intel.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Adam Jackson <ajax@redhat.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1478177609-16762-2-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>