pata_via: clear UDMA transfer mode bit for PIO and MWDMA

Fix register naming while at it.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/pata_via.c

@@ -303,14 +303,21 @@ static void via_do_set_mode(struct ata_port *ap, struct ata_device *adev, int mo
 	}
 
 	/* Set UDMA unless device is not UDMA capable */
-	if (udma_type && t.udma) {
-		u8 cable80_status;
+	if (udma_type) {
+		u8 udma_etc;
 
-		/* Get 80-wire cable detection bit */
-		pci_read_config_byte(pdev, 0x50 + offset, &cable80_status);
-		cable80_status &= 0x10;
+		pci_read_config_byte(pdev, 0x50 + offset, &udma_etc);
 
-		pci_write_config_byte(pdev, 0x50 + offset, ut | cable80_status);
+		/* clear transfer mode bit */
+		udma_etc &= ~0x20;
+
+		if (t.udma) {
+			/* preserve 80-wire cable detection bit */
+			udma_etc &= 0x10;
+			udma_etc |= ut;
+		}
+
+		pci_write_config_byte(pdev, 0x50 + offset, udma_etc);
 	}
 }