drm/i915/hotplug: convert intel_hotplug.[ch] to struct intel_display
Going forward, struct intel_display is the main display device data
pointer. Convert as much as possible of intel_hotplug.[ch] to struct
intel_display.
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://lore.kernel.org/r/cf382dbfacf1445b26fbe1e7c011e7a3ea6e1594.1742481923.git.jani.nikula@intel.com