[libata] Use ATA_UDMAx standard masks when filling driver's udma_mask info

The ATA_UDMAx masks are self-documenting, and far better than manually
writing in the hex mask.

Note that pata_it8213 mask differed from the comment.  Added a FIXME there.

Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/sata_via.c

@@ -223,7 +223,7 @@ static const struct ata_port_info vt6420_port_info = {
 	.flags		= ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY,
 	.pio_mask	= 0x1f,
 	.mwdma_mask	= 0x07,
-	.udma_mask	= 0x7f,
+	.udma_mask	= ATA_UDMA6,
 	.port_ops	= &vt6420_sata_ops,
 };
 
@@ -231,7 +231,7 @@ static struct ata_port_info vt6421_sport_info = {
 	.flags		= ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY,
 	.pio_mask	= 0x1f,
 	.mwdma_mask	= 0x07,
-	.udma_mask	= 0x7f,
+	.udma_mask	= ATA_UDMA6,
 	.port_ops	= &vt6421_sata_ops,
 };
 
@@ -239,7 +239,7 @@ static struct ata_port_info vt6421_pport_info = {
 	.flags		= ATA_FLAG_SLAVE_POSS | ATA_FLAG_NO_LEGACY,
 	.pio_mask	= 0x1f,
 	.mwdma_mask	= 0,
-	.udma_mask	= 0x7f,
+	.udma_mask	= ATA_UDMA6,
 	.port_ops	= &vt6421_pata_ops,
 };