drm/fb-helper: Fix connector ref leak on error

We need to drop the connector references already taken when we
abort in the middle of drm_fb_helper_single_add_all_connectors()

Cc: stable@vger.kernel.org
Cc: Carlos Santa <carlos.santa@intel.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Tested-by: Carlos Santa <carlos.santa@intel.com>
Tested-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1477472755-15288-2-git-send-email-ville.syrjala@linux.intel.com

drivers/gpu/drm/drm_fb_helper.c

@@ -131,7 +131,12 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
 	return 0;
 fail:
 	for (i = 0; i < fb_helper->connector_count; i++) {
-		kfree(fb_helper->connector_info[i]);
+		struct drm_fb_helper_connector *fb_helper_connector =
+			fb_helper->connector_info[i];
+
+		drm_connector_unreference(fb_helper_connector->connector);
+
+		kfree(fb_helper_connector);
 		fb_helper->connector_info[i] = NULL;
 	}
 	fb_helper->connector_count = 0;