ide: drop "PIO data" argument from ide_get_best_pio_mode()

* Drop no longer needed "PIO data" argument from ide_get_best_pio_mode()
  and convert all users accordingly.

* Remove no longer needed ide_pio_data_t.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/legacy/umc8672.c b/drivers/ide/legacy/umc8672.c
index ddc403a..caeebd4 100644
--- a/drivers/ide/legacy/umc8672.c
+++ b/drivers/ide/legacy/umc8672.c
@@ -110,7 +110,7 @@
 	unsigned long flags;
 	ide_hwgroup_t *hwgroup = ide_hwifs[HWIF(drive)->index^1].hwgroup;
 
-	pio = ide_get_best_pio_mode(drive, pio, 4, NULL);
+	pio = ide_get_best_pio_mode(drive, pio, 4);
 	printk("%s: setting umc8672 to PIO mode%d (speed %d)\n",
 		drive->name, pio, pio_to_umc[pio]);
 	spin_lock_irqsave(&ide_lock, flags);