drm/i915/opregion: remove unused lid_state

Not sure if lid_state has ever been used, but at least not for a long
time. Remove it.

Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240117122546.1551400-1-jani.nikula@intel.com