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/ppc/pmac.c b/drivers/ide/ppc/pmac.c
index 6693305..debaa88 100644
--- a/drivers/ide/ppc/pmac.c
+++ b/drivers/ide/ppc/pmac.c
@@ -627,7 +627,7 @@
 	/* which drive is it ? */
 	timings = &pmif->timings[drive->select.b.unit & 0x01];
 
-	pio = ide_get_best_pio_mode(drive, pio, 4, NULL);
+	pio = ide_get_best_pio_mode(drive, pio, 4);
 	cycle_time = ide_pio_cycle_time(drive, pio);
 
 	switch (pmif->kind) {