fsl_pq_mdio: Add Suport for etsec2.0 devices.

This patch adds mdio support for etsec2.0 devices.

Modified the fsl_pq_mdio structure to include the new mdio
members.

Signed-off-by: Sandeep Gopalpet <Sandeep.Kumar@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>