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/sis5513.c b/drivers/ide/pci/sis5513.c
index 1da037f..fed582b 100644
--- a/drivers/ide/pci/sis5513.c
+++ b/drivers/ide/pci/sis5513.c
@@ -531,15 +531,12 @@
 	(void)sis5513_tune_drive(drive, pio);
 }
 
-static int sis5513_tune_chipset (ide_drive_t *drive, u8 xferspeed)
+static int sis5513_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, reg, speed;
 	u32 regdw;
-
-	speed = ide_rate_filter(drive, xferspeed);
+	u8 drive_pci, reg;
 
 	/* See config_art_rwp_pio for drive pci config registers */
 	drive_pci = 0x40;