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/hpt366.c b/drivers/ide/pci/hpt366.c
index ce363c9236..4b6bae8 100644
--- a/drivers/ide/pci/hpt366.c
+++ b/drivers/ide/pci/hpt366.c
@@ -1330,8 +1330,8 @@
 	} else
 		pci_read_config_byte (dev, 0x5a, &scr1);
 
-	if (!hwif->udma_four)
-		hwif->udma_four = (scr1 & ata66) ? 0 : 1;
+	if (hwif->cbl != ATA_CBL_PATA40_SHORT)
+		hwif->cbl = (scr1 & ata66) ? ATA_CBL_PATA40 : ATA_CBL_PATA80;
 
 	hwif->ide_dma_check		= &hpt366_config_drive_xfer_rate;