vmwgfx: Free prefered mode on error path

Signed-off-by: NJakob Bornecrantz <jakob@vmware.com>
Signed-off-by: NThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

@@ -1710,18 +1710,23 @@ int vmw_du_connector_fill_modes(struct drm_connector *connector,
 		mode->hdisplay = du->pref_width;
 		mode->vdisplay = du->pref_height;
 		vmw_guess_mode_timing(mode);
+
 		if (vmw_kms_validate_mode_vram(dev_priv, mode->hdisplay * 2,
 					       mode->vdisplay)) {
 			drm_mode_probed_add(connector, mode);
+		} else {
+			drm_mode_destroy(dev, mode);
+			mode = NULL;
+		}
 
 		if (du->pref_mode) {
 			list_del_init(&du->pref_mode->head);
 			drm_mode_destroy(dev, du->pref_mode);
 		}
 
+		/* mode might be null here, this is intended */
 		du->pref_mode = mode;
 	}
-	}
 
 	for (i = 0; vmw_kms_connector_builtin[i].type != 0; i++) {
 		bmode = &vmw_kms_connector_builtin[i];