drm/i915/mst: Populate connector->ddc

Populate connector->ddc, and thus create the "ddc" symlink
in sysfs for DP MST connectors.

TODO: test that this actually works

References: https://gitlab.freedesktop.org/drm/intel/-/issues/3605Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230829113920.13713-9-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_dp_mst.c

@@ -1104,8 +1104,10 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo
 	drm_dp_mst_get_port_malloc(port);
 
 	connector = &intel_connector->base;
-	ret = drm_connector_init(dev, connector, &intel_dp_mst_connector_funcs,
-				 DRM_MODE_CONNECTOR_DisplayPort);
+	ret = drm_connector_init_with_ddc(dev, connector,
+					  &intel_dp_mst_connector_funcs,
+					  DRM_MODE_CONNECTOR_DisplayPort,
+					  &port->aux.ddc);
 	if (ret) {
 		drm_dp_mst_put_port_malloc(port);
 		intel_connector_free(intel_connector);