TN80xx has same PHY ID as TN2020, but it needs different setting to register
30.93 which used to select line, so we read register 30.32 which has
bit 15:12 to indicate PHY hardware version, for TN20xx we will get 3 or 2,
for TN80xx we will get 5 or 4.
Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>