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/cs5535.c b/drivers/ide/pci/cs5535.c
index 082ca7d..bc00e7b 100644
--- a/drivers/ide/pci/cs5535.c
+++ b/drivers/ide/pci/cs5535.c
@@ -75,7 +75,7 @@
  *
  *	cs5535_set_speed() configures the chipset to a new speed.
  */
-static void cs5535_set_speed(ide_drive_t *drive, u8 speed)
+static void cs5535_set_speed(ide_drive_t *drive, const u8 speed)
 {
 
 	u32 reg = 0, dummy;
@@ -141,7 +141,6 @@
  */
 static int cs5535_set_drive(ide_drive_t *drive, u8 speed)
 {
-	speed = ide_rate_filter(drive, speed);
 	ide_config_drive_speed(drive, speed);
 	cs5535_set_speed(drive, speed);