drm/i915: pass struct intel_connector to connector debugfs fops

Prefer struct intel_connector over struct drm_connector, and unify the
declarations in the fops.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231205134143.2427661-2-jani.nikula@intel.com