net: phy: marvell-88q2xxx: add support for Rev B1 and B2

Different revisions of the Marvell 88q2xxx phy needs different init
sequences.

Add init sequence for Rev B1 and Rev B2. Rev B2 init sequence skips one
register write.

Tested-by: Dimitri Fedrau <dima.fedrau@gmail.com>
Signed-off-by: Gregor Herburger <gregor.herburger@ew.tq-group.com>
Signed-off-by: David S. Miller <davem@davemloft.net>