pata_cmd64x: revert commit d62f5576

Commit d62f5576 (pata_cmd64x: fix handling of address setup timings)
incorrectly called ata_timing_compute() on UDMA mode on 0 @UT leading
to devide by zero fault.  Revert it until better fix is available.
This is reported in bko#16607 by Milan Kocian who also root caused it.

  https://bugzilla.kernel.org/show_bug.cgi?id=16607



Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-root-caused-by: Milan Kocian <milan.kocian@wq.cz>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>