drm/i915: Move all the DP compliance data to a separate struct

This patch does not change anything functionally, just cleans up
the DP compliance related variables and stores them all together
in a separate struct intel_dp_compliance. There is another struct
intel_dp_compliance_data to store all the test data. This makes it easy to
reset the compliance variables through a memset instead of
individual resetting.

v2:
* Removed functional changes for EDID (Jani Nikula)

Reviewed-by: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwl.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1481329371-16306-1-git-send-email-manasi.d.navare@intel.com