media: staging/ipu7: Use v4l2_ctrl_subdev_subscribe_event()

The ipu7-isys driver uses v4l2_ctrl_subscribe_event() to handle control
event subscription on a subdev. While this works, it is the wrong API.
Use the subdev-specific v4l2_ctrl_subdev_subscribe_event() helper
instead.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

drivers/staging/media/ipu7/ipu7-isys-csi2.c

@@ -77,7 +77,7 @@ static int csi2_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
 	case V4L2_EVENT_FRAME_SYNC:
 		return v4l2_event_subscribe(fh, sub, 10, NULL);
 	case V4L2_EVENT_CTRL:
-		return v4l2_ctrl_subscribe_event(fh, sub);
+		return v4l2_ctrl_subdev_subscribe_event(sd, fh, sub);
 	default:
 		return -EINVAL;
 	}