xfrm: remove unused struct xfrm_policy::next

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/xfrm.h

@@ -467,7 +467,6 @@ struct xfrm_policy_walk {
 
 struct xfrm_policy
 {
-	struct xfrm_policy	*next;
 	struct hlist_node	bydst;
 	struct hlist_node	byidx;