[media] v4l2 core: return -ENOTTY if an ioctl doesn't exist

Currently, -EINVAL is used to return either when an IOCTL is not
implemented, or if the ioctl was not implemented.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index 29f7a7d..002ce13 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -543,12 +543,12 @@
 	struct v4l2_fh *vfh = NULL;
 	struct v4l2_format f_copy;
 	int use_fh_prio = 0;
-	long ret = -EINVAL;
+	long ret = -ENOTTY;
 
 	if (ops == NULL) {
 		printk(KERN_WARNING "videodev: \"%s\" has no ioctl_ops.\n",
 				vfd->name);
-		return -EINVAL;
+		return ret;
 	}
 
 	if ((vfd->debug & V4L2_DEBUG_IOCTL) &&