[TG3]: ethtool always report port is TP.

Even with fiber cards ethtool reports that the connected port is TP,
the patch fix this.

Signed-off-by: Karsten Keil <kkeil@suse.de>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>