pata_cmd64x: revert commit d62f557

Commit d62f557 (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>

drivers/ata/pata_cmd64x.c

@@ -121,14 +121,8 @@ static void cmd64x_set_timing(struct ata_port *ap, struct ata_device *adev, u8 m
 
 		if (pair) {
 			struct ata_timing tp;
-
 			ata_timing_compute(pair, pair->pio_mode, &tp, T, 0);
 			ata_timing_merge(&t, &tp, &t, ATA_TIMING_SETUP);
-			if (pair->dma_mode) {
-				ata_timing_compute(pair, pair->dma_mode,
-						&tp, T, 0);
-				ata_timing_merge(&tp, &t, &t, ATA_TIMING_SETUP);
-			}
 		}
 	}