net/phy: Add VSC8662 support

Vitesse VSC8662 is Dual Port 10/100/1000Base-T Phy
Its register set and features are similar to other Vitesse Phys.

Signed-off-by: Sandeep Singh <Sandeep@freescale.com>
Signed-off-by: Andy Fleming <afleming@gmail.com>
Signed-off-by: Shruti Kanetkar <Shruti@Freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>