netfilter: xt_LOG: fix mark logging for IPv6 packets

In dump_ipv6_packet(), the "recurse" parameter is zero only if
dumping contents of a packet embedded into an ICMPv6 error
message. Therefore we want to log packet mark if recurse is
non-zero, not when it is zero.
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/xt_LOG.c

@@ -737,7 +737,7 @@ static void dump_ipv6_packet(struct sbuff *m,
 		dump_sk_uid_gid(m, skb->sk);
 
 	/* Max length: 16 "MARK=0xFFFFFFFF " */
-	if (!recurse && skb->mark)
+	if (recurse && skb->mark)
 		sb_add(m, "MARK=0x%x ", skb->mark);
 }