netfilter: nfnetlink_queue: fix NFQA_VLAN_MAX definition

Should be - 1 as in other _MAX definitions.
Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/uapi/linux/netfilter/nfnetlink_queue.h

@@ -36,7 +36,7 @@ enum nfqnl_vlan_attr {
 	NFQA_VLAN_TCI,			/* __be16 skb htons(vlan_tci) */
 	__NFQA_VLAN_MAX,
 };
-#define NFQA_VLAN_MAX (__NFQA_VLAN_MAX + 1)
+#define NFQA_VLAN_MAX (__NFQA_VLAN_MAX - 1)
 
 enum nfqnl_attr_type {
 	NFQA_UNSPEC,