sata_mv more cosmetic changes

More cosmetic changes; no code changes.

 -- try and improve consistency of naming.
 -- add missing _OFS to tails of register offset definitions.
 -- rename mv_setup_ifctl() to mv_setup_ifcfg(), since that's what it really does.
 -- remove/move some dead comments

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>