net: phy: fix auto negotiation checking for teranetics

When using fiber port, the phy cannot report it's auto negotiation state,
driver should always report auto negotiation is done when using fiber port.

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>