xfrm: Const'ify selector arg to xfrm_dst_update_parent.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index f1f90af..3a4221a 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1525,7 +1525,7 @@
 }
 
 static int inline
-xfrm_dst_update_parent(struct dst_entry *dst, struct xfrm_selector *sel)
+xfrm_dst_update_parent(struct dst_entry *dst, const struct xfrm_selector *sel)
 {
 #ifdef CONFIG_XFRM_SUB_POLICY
 	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;