libata: ata_timing_compute() fixup

XFER_SW_DMA_0 mode should be excluded from the extended cycle timing
computations.
Acked-by: Alan Cox <alan@linux.intel.com>
Noticed-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/libata-core.c

@@ -2938,7 +2938,7 @@ int ata_timing_compute(struct ata_device *adev, unsigned short speed,
 	if (id[ATA_ID_FIELD_VALID] & 2) {	/* EIDE drive */
 		memset(&p, 0, sizeof(p));
 
-		if (speed >= XFER_PIO_0 && speed <= XFER_SW_DMA_0) {
+		if (speed >= XFER_PIO_0 && speed < XFER_SW_DMA_0) {
 			if (speed <= XFER_PIO_2)
 				p.cycle = p.cyc8b = id[ATA_ID_EIDE_PIO];
 			else if ((speed <= XFER_PIO_4) ||