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/tc86c001.c b/drivers/ide/pci/tc86c001.c
index ec79bac..e542577 100644
--- a/drivers/ide/pci/tc86c001.c
+++ b/drivers/ide/pci/tc86c001.c
@@ -13,14 +13,12 @@
 #include <linux/pci.h>
 #include <linux/ide.h>
 
-static int tc86c001_tune_chipset(ide_drive_t *drive, u8 speed)
+static int tc86c001_tune_chipset(ide_drive_t *drive, const u8 speed)
 {
 	ide_hwif_t *hwif	= HWIF(drive);
 	unsigned long scr_port	= hwif->config_data + (drive->dn ? 0x02 : 0x00);
 	u16 mode, scr		= hwif->INW(scr_port);
 
-	speed = ide_rate_filter(drive, speed);
-
 	switch (speed) {
 		case XFER_UDMA_4:	mode = 0x00c0; break;
 		case XFER_UDMA_3:	mode = 0x00b0; break;