V4L/DVB (5103): Fix vidioc_g_tuner handling

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/cx88/cx88-video.c b/drivers/media/video/cx88/cx88-video.c
index 8ba9942..d388a42 100644
--- a/drivers/media/video/cx88/cx88-video.c
+++ b/drivers/media/video/cx88/cx88-video.c
@@ -1301,6 +1301,8 @@
 
 	if (unlikely(UNSET == core->tuner_type))
 		return -EINVAL;
+	if (0 != t->index)
+		return -EINVAL;
 
 	strcpy(t->name, "Television");
 	t->type       = V4L2_TUNER_ANALOG_TV;