ide: add PIO masks

* Add ATA_PIO[0-6] defines to <linux/ata.h>.

* Add ->pio_mask field to ide_pci_device_t and ide_hwif_t.

* Add PIO masks to host drivers.

<linux/ata.h> change ACK-ed by Jeff Garzik <jeff@garzik.org>.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/sgiioc4.c b/drivers/ide/pci/sgiioc4.c
index ed983b5..5714576 100644
--- a/drivers/ide/pci/sgiioc4.c
+++ b/drivers/ide/pci/sgiioc4.c
@@ -586,6 +586,7 @@
 	hwif->ultra_mask = 0x0;	/* Disable Ultra DMA */
 	hwif->mwdma_mask = 0x2;	/* Multimode-2 DMA  */
 	hwif->swdma_mask = 0x2;
+	hwif->pio_mask = 0x00;
 	hwif->tuneproc = NULL;	/* Sets timing for PIO mode */
 	hwif->speedproc = NULL;	/* Sets timing for DMA &/or PIO modes */
 	hwif->selectproc = NULL;/* Use the default routine to select drive */