drm/915: Parsing the missed out DTD fields from the VBT

The upper bits of the vsync width, vsync offset and hsync width
were not parsed from the VBT. Parse these fields in this patch.

V2: Renamed lvds dvo timing structure members and code identation
fix (Jani's review comments)
V3: Corrected commit message, used "from the VBT"

Signed-off-by: Vincente Tsou <vincente.tsou@intel.com>
Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1482430993-3265-1-git-send-email-madhav.chauhan@intel.com