[BNX2]: Add ethtool support for remote PHY.

Modify the driver's ethtool_ops->get_settings and set_settings
functions to support remote PHY.  Users control the remote copper
PHY settings by specifying link settings for the tp (twisted pair)
port.

The nway_reset function is also modified to support remote PHY.
mii-tool operations are not supported on remote PHY and we will
return -EOPNOTSUPP.

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