libata: reimplement ata_acpi_cbl_80wire() using ata_acpi_gtm_xfermask()

Reimplement ata_acpi_cbl_80wire() using ata_acpi_gtm_xfermask() and
while at it relocate the function below ata_acpi_gtm_xfermask().

New ata_acpi_cbl_80wire() implementation takes @gtm, in both pata_via
and pata_amd, use the initial GTM value.  Both are trying to peek
initial BIOS configuration, so using initial caching value makes
sense.  This fixes ACPI part of cable detection in pata_amd which
previously always returned 0 because configuring PIO0 during reset
clears DMA configuration.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/pata_via.c b/drivers/ata/pata_via.c
index 453d72b..39627ab 100644
--- a/drivers/ata/pata_via.c
+++ b/drivers/ata/pata_via.c
@@ -185,7 +185,8 @@
 	if (ata66 & (0x10100000 >> (16 * ap->port_no)))
 		return ATA_CBL_PATA80;
 	/* Check with ACPI so we can spot BIOS reported SATA bridges */
-	if (ata_acpi_cbl_80wire(ap))
+	if (ata_acpi_init_gtm(ap) &&
+	    ata_acpi_cbl_80wire(ap, ata_acpi_init_gtm(ap)))
 		return ATA_CBL_PATA80;
 	return ATA_CBL_PATA40;
 }