ide: use only ->set_pio_mode method for programming PIO modes (take 2)

Use ->set_pio_mode method to program PIO modes in ide_set_xfer_rate()
(the only place which used ->speedproc to program PIO modes) and remove
handling of PIO modes from all ->speedproc implementations.

v2:
* Fix pmac_ide_tune_chipset() comment.

There should be no functionality changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/cs5520.c b/drivers/ide/pci/cs5520.c
index e6af534..1217d2a 100644
--- a/drivers/ide/pci/cs5520.c
+++ b/drivers/ide/pci/cs5520.c
@@ -66,30 +66,13 @@
 	{1, 2, 1}
 };
 
-static int cs5520_tune_chipset(ide_drive_t *drive, const u8 speed)
+static void cs5520_set_pio_mode(ide_drive_t *drive, const u8 pio)
 {
 	ide_hwif_t *hwif = HWIF(drive);
 	struct pci_dev *pdev = hwif->pci_dev;
-	int pio = speed;
-	u8 reg;
 	int controller = drive->dn > 1 ? 1 : 0;
+	u8 reg;
 
-	switch(speed)
-	{
-		case XFER_PIO_4:
-		case XFER_PIO_3:
-		case XFER_PIO_2:
-		case XFER_PIO_1:
-		case XFER_PIO_0:
-			pio -= XFER_PIO_0;
-			break;
-		default:
-			pio = 0;
-			printk(KERN_ERR "cs55x0: bad ide timing.\n");
-	}
-	
-	printk("PIO clocking = %d\n", pio);
-	
 	/* FIXME: if DMA = 1 do we need to set the DMA bit here ? */
 
 	/* 8bit CAT/CRT - 8bit command timing for channel */
@@ -114,12 +97,21 @@
 	reg |= 1<<((drive->dn&1)+5);
 	outb(reg, hwif->dma_base + 0x02 + 8*controller);
 
-	return ide_config_drive_speed(drive, speed);
+	(void)ide_config_drive_speed(drive, XFER_PIO_0 + pio);
 }
 
-static void cs5520_set_pio_mode(ide_drive_t *drive, const u8 pio)
+static int cs5520_tune_chipset(ide_drive_t *drive, const u8 speed)
 {
-	cs5520_tune_chipset(drive, XFER_PIO_0 + pio);
+	printk(KERN_ERR "cs55x0: bad ide timing.\n");
+
+	cs5520_set_pio_mode(drive, 0);
+
+	/*
+	 * FIXME: this is incorrect to return zero here but
+	 * since all users of ide_set_xfer_rate() ignore
+	 * the return value it is not a problem currently
+	 */
+	return 0;
 }
 
 static int cs5520_config_drive_xfer_rate(ide_drive_t *drive)