netfilter: bridge: refactor clearing BRNF_NF_BRIDGE_PREROUTING

use binary AND on complement of BRNF_NF_BRIDGE_PREROUTING to unset
bit in nf_bridge->mask.
Signed-off-by: NBernhard Thaler <bernhard.thaler@wvnet.at>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

net/bridge/br_netfilter.c

@@ -290,7 +290,7 @@ static int br_nf_pre_routing_finish_ipv6(struct sock *sk, struct sk_buff *skb)
 		skb->pkt_type = PACKET_OTHERHOST;
 		nf_bridge->pkt_otherhost = false;
 	}
-	nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
+	nf_bridge->mask &= ~BRNF_NF_BRIDGE_PREROUTING;
 
 	rt = bridge_parent_rtable(nf_bridge->physindev);
 	if (!rt) {
@@ -415,7 +415,7 @@ static int br_nf_pre_routing_finish(struct sock *sk, struct sk_buff *skb)
 		skb->pkt_type = PACKET_OTHERHOST;
 		nf_bridge->pkt_otherhost = false;
 	}
-	nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
+	nf_bridge->mask &= ~BRNF_NF_BRIDGE_PREROUTING;
 	if (daddr_was_changed(skb, nf_bridge)) {
 		if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
 			struct in_device *in_dev = __in_dev_get_rcu(dev);