net: phy: marvell: add errata w/a for 88E151* chips

As per Marvell Release Notes - Alaska 88E1510/88E1518/88E1512/88E1514
Rev A0, Errata Section 3.1 Marvell PHY has an errata which requires
that certain registers get written in order to restart
autonegotiation.

Signed-off-by: Hao Zhang <hzhang@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
Reviewed-by: Stefan Roese <sr@denx.de>