drm/edid: Don't send bogus aspect ratios in AVI infoframes

If the user mode would specify an aspect ratio other than 4:3 or 16:9
we now silently ignore it. Maybe a better apporoach is to return an
error? Let's try that.

Also we must be careful that we don't try to send illegal picture
aspect in the infoframe as it's only capable of signalling none,
4:3, and 16:9. Currently we're sending these bogus infoframes
whenever the cea mode specifies some other aspect ratio.

Cc: Shashank Sharma <shashank.sharma@intel.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Jose Abreu <Jose.Abreu@synopsys.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1525777785-9740-5-git-send-email-ankit.k.nautiyal@intel.com