gianfar: Create net device with carrier down

The device's carrier status is controlled via the functions
netif_carrier_on() and netif_carrier_off().  These set or clear a bit
indicating the carrier (aka lower level link) is down, and if the state
changed, they fire off a routing netlink event.

Add a call to netif_carrier_off() before register_netdev() so that the
newly created device will be set to carrier down.  Then when the carrier
comes up for the first time, a netlink event will be generated, as the
carrier changed from down to up.  Otherwise the initial carrier up will
appear to be changing the status from up to up, and so no event is
generated since that's not a change.

Signed-off-by: Trent Piepho <tpiepho@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>