drm/i915/dvo: convert intel_dvo.[ch] to struct intel_display

Going forward, struct intel_display is the main display device data
pointer. Convert intel_dvo.[ch] to struct intel_display.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/a78b5c8d0030957523eb467401b06e2d290cf14d.1742554320.git.jani.nikula@intel.com


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