[media] uvcvideo: Return -EACCES when trying to set a read-only control

Commit ba68c8530a263dc4de440fa10bb20a1c5b9d4ff5 (Partly revert "[media]
uvcvideo: Set error_idx properly for extended controls API failures")
also reverted part of commit 30ecb936cbcd83e3735625ac63e1b4466546f5fe
("uvcvideo: Return -EACCES when trying to access a read/write-only
control") by mistake. Fix it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/usb/uvc/uvc_ctrl.c

@@ -1431,8 +1431,10 @@ int uvc_ctrl_set(struct uvc_video_chain *chain,
 	int ret;
 
 	ctrl = uvc_find_control(chain, xctrl->id, &mapping);
-	if (ctrl == NULL || (ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR) == 0)
+	if (ctrl == NULL)
 		return -EINVAL;
+	if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR))
+		return -EACCES;
 
 	/* Clamp out of range values. */
 	switch (mapping->v4l2_type) {