drm: Add aspect ratio parsing in DRM layer

Current DRM layer functions don't parse aspect ratio information
while converting a user mode->kernel mode or vice versa. This
causes modeset to pick mode with wrong aspect ratio, eventually
causing failures in HDMI compliance test cases, due to wrong VIC.

This patch adds aspect ratio information in DRM's mode conversion
and mode comparision functions, to make sure kernel picks mode
with right aspect ratio (as per the VIC).

V2: Addressed review comments from Sean:
- Fix spellings/typo
- No need to handle aspect ratio none
- Add a break, for default case too
V3: Rebase
V4: Added r-b from Jose

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Lin, Jia <lin.a.jia@intel.com>
Signed-off-by: Akashdeep Sharma <akashdeep.sharma@intel.com>
Reviewed-by: Jim Bride <jim.bride@linux.intel.com>
Reviewed-by: Jose Abreu <Jose.Abreu@synopsys.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1476705880-15600-3-git-send-email-shashank.sharma@intel.com