net: bridge: remove unneeded variable 'err'

function br_multicast_toggle now always return 0,
so the variable 'err' is unneeded.
Also cleanup dead branch in br_changelink.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 935495b..9c07591 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -1175,9 +1175,7 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 	if (data[IFLA_BR_MCAST_SNOOPING]) {
 		u8 mcast_snooping = nla_get_u8(data[IFLA_BR_MCAST_SNOOPING]);
 
-		err = br_multicast_toggle(br, mcast_snooping);
-		if (err)
-			return err;
+		br_multicast_toggle(br, mcast_snooping);
 	}
 
 	if (data[IFLA_BR_MCAST_QUERY_USE_IFADDR]) {