ata_piix: fix MWDMA handling on PIIX3

Fix erroneous check for ap->udma_mask in do_pata_set_dmamode()
resulting in controller not being programmed properly for MWDMA.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/ata_piix.c

@@ -869,11 +869,11 @@ static void do_pata_set_dmamode(struct ata_port *ap, struct ata_device *adev, in
 				(timings[pio][1] << 8);
 		}
 
-		if (ap->udma_mask) {
+		if (ap->udma_mask)
 			udma_enable &= ~(1 << devid);
+
 		pci_write_config_word(dev, master_port, master_data);
 	}
-	}
 	/* Don't scribble on 0x48 if the controller does not support UDMA */
 	if (ap->udma_mask)
 		pci_write_config_byte(dev, 0x48, udma_enable);