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/ppc/pmac.c b/drivers/ide/ppc/pmac.c
index debaa88..33630ad 100644
--- a/drivers/ide/ppc/pmac.c
+++ b/drivers/ide/ppc/pmac.c
@@ -1248,6 +1248,7 @@
 	hwif->cbl = pmif->cable_80 ? ATA_CBL_PATA80 : ATA_CBL_PATA40;
 	hwif->drives[0].unmask = 1;
 	hwif->drives[1].unmask = 1;
+	hwif->pio_mask = ATA_PIO4;
 	hwif->tuneproc = pmac_ide_tuneproc;
 	if (pmif->kind == controller_un_ata6
 	    || pmif->kind == controller_k2_ata6