[media] v4l2-ioctl.c: fix enum_freq_bands handling

If the driver supports enum_freq_bands, but only for certain device
nodes, then it may return -ENOTTY. But in that case the code should
fall into the fall-back case where the current tuner/modulator range
is returned.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/v4l2-core/v4l2-ioctl.c

@@ -2042,8 +2042,11 @@ static int v4l_enum_freq_bands(const struct v4l2_ioctl_ops *ops,
 		if (type != p->type)
 			return -EINVAL;
 	}
-	if (ops->vidioc_enum_freq_bands)
-		return ops->vidioc_enum_freq_bands(file, fh, p);
+	if (ops->vidioc_enum_freq_bands) {
+		err = ops->vidioc_enum_freq_bands(file, fh, p);
+		if (err != -ENOTTY)
+			return err;
+	}
 	if (is_valid_ioctl(vfd, VIDIOC_G_TUNER)) {
 		struct v4l2_tuner t = {
 			.index = p->tuner,