drm/i915/wa: convert intel_display_wa.[ch] to struct intel_display

Going forward, struct intel_display is the main display device data
pointer. Convert as much as possible of intel_display_wa.[ch] to struct
intel_display.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/821937f9fcdcb7d5516be0c48c2cee009936ecb8.1742906146.git.jani.nikula@intel.com


Signed-off-by: Jani Nikula <jani.nikula@intel.com>