ipv6: Fix return of xfrm6_tunnel_rcv()

Like ipv4, just return xfrm6_rcv_spi()'s return value directly.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/xfrm6_tunnel.c

@@ -241,7 +241,7 @@ static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 	__be32 spi;
 
 	spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
-	return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi) > 0 ? : 0;
+	return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi);
 }
 
 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,