drm/i915/edp: use MSO pixel overlap from DisplayID data

Now that we have MSO pixel overlap in display info, use it.

Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/87d8d80ba205eb2ecb50f613219e0a821a842616.1630419362.git.jani.nikula@intel.com