[IPSEC]: Use xfrm4_rcv in xfrm4_tunnel

This is a trivial patch to use xfrm4_rcv in xfrm4_tunnel.  It doesn't
need the extra argument provided by xfrm4_rcv_encap.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@redhat.com>

net/ipv4/xfrm4_tunnel.c

@@ -68,7 +68,7 @@ static int ipip_rcv(struct sk_buff *skb)
 	if (handler && handler->handler(skb) == 0)
 		return 0;
 
-	return xfrm4_rcv_encap(skb, 0);
+	return xfrm4_rcv(skb);
 }
 
 static void ipip_err(struct sk_buff *skb, u32 info)