bridge: fix build for CONFIG_SYSFS disabled

Fix build when CONFIG_SYSFS is not enabled:
net/bridge/br_if.c:136: error: 'struct net_bridge_port' has no member named 'sysfs_name'

Note: dev->name == sysfs_name except when change name is in
progress, and we are protected from that by RTNL mutex.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_if.c

@@ -133,7 +133,7 @@ static void del_nbp(struct net_bridge_port *p)
 	struct net_bridge *br = p->br;
 	struct net_device *dev = p->dev;
 
-	sysfs_remove_link(br->ifobj, p->sysfs_name);
+	sysfs_remove_link(br->ifobj, p->dev->name);
 
 	dev_set_promiscuity(dev, -1);