ide: IORDY handling fixes

Add ide_pio_need_iordy() helper and convert host drivers to use it.

This fixes it8172, it8213, pdc202xx_old, piix, slc90e66 and siimage
host drivers to handle IORDY correctly.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/it8213.c

@@ -50,7 +50,7 @@ static void it8213_set_pio_mode(ide_drive_t *drive, const u8 pio)
 		control |= 1;	/* Programmable timing on */
 	if (drive->media != ide_disk)
 		control |= 4;	/* ATAPI */
-	if (pio > 2)
+	if (ide_pio_need_iordy(drive, pio))
 		control |= 2;	/* IORDY */
 	if (is_slave) {
 		master_data |=  0x4000;