[TG3]: Fix race condition when calling register_netdev().

Hot-plug scripts can call tg3_open() as soon as register_netdev() is
called in tg3_init_one().  We need to call pci_set_drvdata() before
register_netdev(), and netif_carrier_off() needs to be moved to
tg3_open() to avoid race conditions.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>