ide: add short cables support

This patch allows users to override both host and device side cable detection
with "ideX=ata66" kernel parameter.  Thanks to this it should be now possible
to use UDMA > 2 modes on systems (laptops mainly) which use short 40-pin cable
instead of 80-pin one.

Next patches add automatic detection of some systems using short cables.

Changes:

* Rename hwif->udma_four to hwif->cbl and make it u8.

* Convert all existing users accordingly (use ATA_CBL_* defines while at it).  

* Add ATA_CBL_PATA40_SHORT support to ide-iops.c:eighty_ninty_three().

* Use ATA_CBL_PATA40_SHORT for "ideX=ata66" kernel parameter.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Reviewed-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
diff --git a/drivers/ide/pci/atiixp.c b/drivers/ide/pci/atiixp.c
index 8ab33fa..2761510 100644
--- a/drivers/ide/pci/atiixp.c
+++ b/drivers/ide/pci/atiixp.c
@@ -264,10 +264,11 @@
 	hwif->swdma_mask = 0x04;
 
 	pci_read_config_byte(pdev, ATIIXP_IDE_UDMA_MODE + ch, &udma_mode);
+
 	if ((udma_mode & 0x07) >= 0x04 || (udma_mode & 0x70) >= 0x40)
-		hwif->udma_four = 1;
+		hwif->cbl = ATA_CBL_PATA80;
 	else
-		hwif->udma_four = 0;
+		hwif->cbl = ATA_CBL_PATA40;
 
 	hwif->dma_host_on = &atiixp_dma_host_on;
 	hwif->dma_host_off = &atiixp_dma_host_off;