[BRIDGE]: adding new device to bridge should enable if up

One change introduced by the workqueue removal patch is that adding an
interface that is up to a bridge which is also up does not ever call
br_stp_enable_port(), leaving the port in DISABLED state until we do
ifconfig down and up or link events occur.

The following patch to the br_add_if function fixes it.
This is a regression introduced in 2.6.21.

Submitted-by: Aji_Srinivas@emc.com
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_if.c

@@ -428,6 +428,10 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 	spin_lock_bh(&br->lock);
 	br_stp_recalculate_bridge_id(br);
 	br_features_recompute(br);
+
+	if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
+	    (br->dev->flags & IFF_UP))
+		br_stp_enable_port(p);
 	spin_unlock_bh(&br->lock);
 
 	dev_set_mtu(br->dev, br_min_mtu(br));