[media] v4l2-ioctl: add ctrl_handler to v4l2_fh

This is required to implement control events and is also needed to allow
for per-filehandle control handlers.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/v4l2-fh.c b/drivers/media/video/v4l2-fh.c
index 717f71e..8635011 100644
--- a/drivers/media/video/v4l2-fh.c
+++ b/drivers/media/video/v4l2-fh.c
@@ -32,6 +32,8 @@
 int v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
 {
 	fh->vdev = vdev;
+	/* Inherit from video_device. May be overridden by the driver. */
+	fh->ctrl_handler = vdev->ctrl_handler;
 	INIT_LIST_HEAD(&fh->list);
 	set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
 	fh->prio = V4L2_PRIORITY_UNSET;