The only public release of the 6042/7042 chips was/is revision "B0".
Remove code that attempted to deal with earlier, non-released revs.
This matches the logic of the current Marvell "proprietary" driver.

Also, bump up the sata_mv version number, to reflect this batch of erratas.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>