netfilter: connlimit: fix UP build

cannot use ARRAY_SIZE() if spinlock_t is empty struct.

Fixes: 1442e7507dd597 ("netfilter: connlimit: use keyed locks")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/xt_connlimit.c

@@ -377,7 +377,7 @@ static int connlimit_mt_check(const struct xt_mtchk_param *par)
 		return -ENOMEM;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(info->data->locks); ++i)
+	for (i = 0; i < CONNLIMIT_LOCK_SLOTS; ++i)
 		spin_lock_init(&info->data->locks[i]);
 
 	for (i = 0; i < ARRAY_SIZE(info->data->climit_root4); ++i)