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/slc90e66.c b/drivers/ide/pci/slc90e66.c
index 628b066..cc93535 100644
--- a/drivers/ide/pci/slc90e66.c
+++ b/drivers/ide/pci/slc90e66.c
@@ -102,12 +102,11 @@
 	(void) ide_config_drive_speed(drive, XFER_PIO_0 + pio);
 }
 
-static int slc90e66_tune_chipset (ide_drive_t *drive, u8 xferspeed)
+static int slc90e66_tune_chipset(ide_drive_t *drive, const u8 speed)
 {
 	ide_hwif_t *hwif	= HWIF(drive);
 	struct pci_dev *dev	= hwif->pci_dev;
 	u8 maslave		= hwif->channel ? 0x42 : 0x40;
-	u8 speed		= ide_rate_filter(drive, xferspeed);
 	int sitre = 0, a_speed	= 7 << (drive->dn * 4);
 	int u_speed = 0, u_flag = 1 << drive->dn;
 	u16			reg4042, reg44, reg48, reg4a;