drm/i915/dsi: convert intel_dsi_vbt.[ch] to struct intel_display

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

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/d2a327c7121263cd67986a2d9199e18d7bf03acd.1742554320.git.jani.nikula@intel.com


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