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/alim15x3.c b/drivers/ide/pci/alim15x3.c
index 27525ec..d52c54b 100644
--- a/drivers/ide/pci/alim15x3.c
+++ b/drivers/ide/pci/alim15x3.c
@@ -594,7 +594,7 @@
  *	FIXME: frobs bits that are not defined on newer ALi devicea
  */
 
-static unsigned int __devinit ata66_ali15x3 (ide_hwif_t *hwif)
+static u8 __devinit ata66_ali15x3(ide_hwif_t *hwif)
 {
 	struct pci_dev *dev	= hwif->pci_dev;
 	unsigned int ata66	= 0;
@@ -657,7 +657,7 @@
 
 	local_irq_restore(flags);
 
-	return(ata66);
+	return ata66 ? ATA_CBL_PATA80 : ATA_CBL_PATA40;
 }
 
 /**
@@ -708,8 +708,9 @@
 		hwif->dma_setup = &ali15x3_dma_setup;
 		if (!noautodma)
 			hwif->autodma = 1;
-		if (!(hwif->udma_four))
-			hwif->udma_four = ata66_ali15x3(hwif);
+
+		if (hwif->cbl != ATA_CBL_PATA40_SHORT)
+			hwif->cbl = ata66_ali15x3(hwif);
 	}
 	hwif->drives[0].autodma = hwif->autodma;
 	hwif->drives[1].autodma = hwif->autodma;