[media] uvcvideo: Lock controls mutex when querying menus

uvc_find_control() must be called with the controls mutex locked. Fix
uvc_query_v4l2_menu() accordingly.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h
index d97cf6d..4520924 100644
--- a/drivers/media/video/uvc/uvcvideo.h
+++ b/drivers/media/video/uvc/uvcvideo.h
@@ -606,10 +606,10 @@
 extern int uvc_status_resume(struct uvc_device *dev);
 
 /* Controls */
-extern struct uvc_control *uvc_find_control(struct uvc_video_chain *chain,
-		__u32 v4l2_id, struct uvc_control_mapping **mapping);
 extern int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
 		struct v4l2_queryctrl *v4l2_ctrl);
+extern int uvc_query_v4l2_menu(struct uvc_video_chain *chain,
+		struct v4l2_querymenu *query_menu);
 
 extern int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
 		const struct uvc_control_mapping *mapping);