IDE mode of MCP89 on MBP 7,1 doesn't set DMA enable bits in the BMDMA
status register.  Make the following changes to work around the problem.

* Instead of using hard coded 1 in id->driver_data as class code
  match, use ATA_GEN_CLASS_MATCH and carry the matched id in
  host->private_data.

* Instead of matching PCI_VENDOR_ID_CENATEK, use ATA_GEN_FORCE_DMA
  flag in id instead.

* Add ATA_GEN_FORCE_DMA to the id entry of MBP 7,1.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Peer Chen <pchen@nvidia.com>
Cc: stable@kernel.org
Reported-by: Anders Østhus <grapz666@gmail.com>
Reported-by: Andreas Graf <andreas_graf@csgraf.de>
Reported-by: Benoit Gschwind <gschwind@gnu-log.net>
Reported-by: Damien Cassou <damien.cassou@gmail.com>
Reported-by: tixetsal@juno.com
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>