gre6: use log_ecn_error module parameter in ip6_tnl_rcv()

After commit 308edfdf ("gre6: Cleanup GREv6 receive path, call
common GRE functions") it's not used anywhere in the module, but
previously was used in ip6gre_rcv().

Fixes: 308edfdf ("gre6: Cleanup GREv6 receive path, call common GRE functions")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ip6_gre.c

@@ -460,7 +460,7 @@ static int ip6gre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
 				      &ipv6h->saddr, &ipv6h->daddr, tpi->key,
 				      tpi->proto);
 	if (tunnel) {
-		ip6_tnl_rcv(tunnel, skb, tpi, NULL, false);
+		ip6_tnl_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
 
 		return PACKET_RCVD;
 	}