net/fm: Add QSGMII PCS init

net/fm: Add QSGMII PCS init

QSGMII PCS needed to be programmed same as SGMII PCS, and there are
four ports in QSGMII PCS, port 0, 1, 2, 3, all the four ports shared
port 0's MDIO controller, so when programming port 0, we continue to
program other three ports.

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: Mingkai Hu <Mingkai.Hu@freescale.com>
Signed-off-by: Gong Qianyu <Qianyu.Gong@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>