tg3: Fix race for querying speed/duplex

When driver signals carrier up via netif_carrier_on() its internal
link_up state isn't updated immediately. This leads to inconsistent
speed/duplex in /proc/net/bonding/bondX where the speed and duplex
is shown as unknown while ethtool shows correct values. Fix this by
using netif_carrier_ok() for link checking in get_ksettings function.

Fixes: 84421b99cedc ("tg3: Update link_up flag for phylib devices")
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>