[NETFILTER]: nf_conntrack: switch rwlock to spinlock

With the RCU conversion only write_lock usages of nf_conntrack_lock are
left (except one read_lock that should actually use write_lock in the
H.323 helper). Switch to a spinlock.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c
index 872c1aa..0256305 100644
--- a/net/netfilter/nf_conntrack_h323_main.c
+++ b/net/netfilter/nf_conntrack_h323_main.c
@@ -1415,7 +1415,7 @@
 		nf_ct_refresh(ct, skb, info->timeout * HZ);
 
 		/* Set expect timeout */
-		read_lock_bh(&nf_conntrack_lock);
+		spin_lock_bh(&nf_conntrack_lock);
 		exp = find_expect(ct, &ct->tuplehash[dir].tuple.dst.u3,
 				  info->sig_port[!dir]);
 		if (exp) {
@@ -1425,7 +1425,7 @@
 			NF_CT_DUMP_TUPLE(&exp->tuple);
 			set_expect_timeout(exp, info->timeout);
 		}
-		read_unlock_bh(&nf_conntrack_lock);
+		spin_unlock_bh(&nf_conntrack_lock);
 	}
 
 	return 0;