media: ivtv: update *pos correctly in ivtv_read_pos()

We had intended to update *pos, but the current code is a no-op.

Fixes: 1a0adaf3 ("V4L/DVB (5345): ivtv driver for Conexant cx23416/cx23415 MPEG encoder/decoder")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/pci/ivtv/ivtv-fileops.c

@@ -420,7 +420,7 @@ static ssize_t ivtv_read_pos(struct ivtv_stream *s, char __user *ubuf, size_t co
 
 	IVTV_DEBUG_HI_FILE("read %zd from %s, got %zd\n", count, s->name, rc);
 	if (rc > 0)
-		pos += rc;
+		*pos += rc;
 	return rc;
 }