ibm_newemac: emac_close() needs to call netif_carrier_off()

When ibm_newemac netdev instance is shutdown with "ifconfig down",
the netdev interface does not go properly down. netif_carrier_ok()
keeps returning TRUE even after "ifconfig down".

The problem can be seen when ibm_newemac instances are slaves of
a bonding interface. The bonding interface code uses netif_carrier_ok()
to determine the link status of its slaves. When ibm_newemac slave is
shutdown with "ifconfig down", the bonding interface won't detect any
link status change because netif_carrier_ok() keeps returning TRUE.
Signed-off-by: NPetri Gynther <pgynther@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ibm_newemac/core.c

@@ -1305,6 +1305,8 @@ static int emac_close(struct net_device *ndev)
 
 	free_irq(dev->emac_irq, dev);
 
+	netif_carrier_off(ndev);
+
 	return 0;
 }