media: atomisp: Use video_dev.lock for ioctl locking

Set video_dev.lock to point to isp->mutex so that the core does
the locking surroundig ioctls for us and drop all the now no longer
necessary (and conflicting) locking from the ioctl handling code.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/staging/media/atomisp/pci/atomisp_v4l2.c

@@ -441,6 +441,7 @@ int atomisp_video_init(struct atomisp_video_pipe *video, const char *name,
 		video->pad.flags = MEDIA_PAD_FL_SINK;
 		video->vdev.fops = &atomisp_fops;
 		video->vdev.ioctl_ops = &atomisp_ioctl_ops;
+		video->vdev.lock = &video->isp->mutex;
 		break;
 	default:
 		return -EINVAL;