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>

drivers/ide/pci/it8213.c

@@ -276,6 +276,7 @@ static void __devinit init_hwif_it8213(ide_hwif_t *hwif)
 		.enablebits	= {{0x41,0x80,0x80}}, \
 		.bootable	= ON_BOARD,		\
 		.host_flags	= IDE_HFLAG_SINGLE,	\
+		.pio_mask	= ATA_PIO4,		\
 	}
 
 static ide_pci_device_t it8213_chipsets[] __devinitdata = {