media: uvcvideo: Annotate lock requirements for uvc_ctrl_set

Make it explicit that the function is always called with ctrl_mutex
being held.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Link: https://lore.kernel.org/r/20241203-uvc-fix-async-v6-4-26c867231118@chromium.org
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Author: ribalda

drivers/media/usb/uvc/uvc_ctrl.c

@@ -1981,6 +1981,8 @@ int uvc_ctrl_set(struct uvc_fh *handle,
 	s32 max;
 	int ret;
 
+	lockdep_assert_held(&chain->ctrl_mutex);
+
 	if (__uvc_query_v4l2_class(chain, xctrl->id, 0) >= 0)
 		return -EACCES;