V4L/DVB (5103): Fix vidioc_g_tuner handling

Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/cx88/cx88-video.c

@@ -1301,6 +1301,8 @@ static int vidioc_g_tuner (struct file *file, void *priv,
 
 	if (unlikely(UNSET == core->tuner_type))
 		return -EINVAL;
+	if (0 != t->index)
+		return -EINVAL;
 
 	strcpy(t->name, "Television");
 	t->type       = V4L2_TUNER_ANALOG_TV;