ide: move ide_rate_filter() calls to the upper layer (take 2)

* Move ide_rate_filter() calls from host drivers to IDE core.

* Make ide_rate_filter() static.

* Make 'speed' argument of ->speedproc const.

v2:
* Fix it8213_tune_chipset() comment.

There should be no functionality changes caused by this patch.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/pdc202xx_old.c b/drivers/ide/pci/pdc202xx_old.c
index e19a891..e7a5e30 100644
--- a/drivers/ide/pci/pdc202xx_old.c
+++ b/drivers/ide/pci/pdc202xx_old.c
@@ -63,12 +63,11 @@
 
 static void pdc_old_disable_66MHz_clock(ide_hwif_t *);
 
-static int pdc202xx_tune_chipset (ide_drive_t *drive, u8 xferspeed)
+static int pdc202xx_tune_chipset(ide_drive_t *drive, const u8 speed)
 {
 	ide_hwif_t *hwif	= HWIF(drive);
 	struct pci_dev *dev	= hwif->pci_dev;
 	u8 drive_pci		= 0x60 + (drive->dn << 2);
-	u8 speed		= ide_rate_filter(drive, xferspeed);
 
 	u8			AP = 0, BP = 0, CP = 0;
 	u8			TA = 0, TB = 0, TC = 0;