media: omap3isp: Fix missing unlock in isp_subdev_notifier_complete()

Add the missing unlock before return from function
isp_subdev_notifier_complete() in the init error
handling case.

Fixes: ba689d93 ("media: omap3isp: Acquire graph mutex for graph traversal")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/omap3isp/isp.c

@@ -2037,8 +2037,10 @@ static int isp_subdev_notifier_complete(struct v4l2_async_notifier *async)
 	mutex_lock(&isp->media_dev.graph_mutex);
 
 	ret = media_entity_enum_init(&isp->crashed, &isp->media_dev);
-	if (ret)
+	if (ret) {
+		mutex_unlock(&isp->media_dev.graph_mutex);
 		return ret;
+	}
 
 	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 		if (sd->notifier != &isp->notifier)