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/ppc/pmac.c b/drivers/ide/ppc/pmac.c
index 222adcb..284bb7c 100644
--- a/drivers/ide/ppc/pmac.c
+++ b/drivers/ide/ppc/pmac.c
@@ -411,7 +411,6 @@
 
 static void pmac_ide_setup_dma(pmac_ide_hwif_t *pmif, ide_hwif_t *hwif);
 static int pmac_ide_build_dmatable(ide_drive_t *drive, struct request *rq);
-static int pmac_ide_tune_chipset(ide_drive_t *drive, u8 speed);
 static void pmac_ide_tuneproc(ide_drive_t *drive, u8 pio);
 static void pmac_ide_selectproc(ide_drive_t *drive);
 static void pmac_ide_kauai_selectproc(ide_drive_t *drive);
@@ -920,16 +919,13 @@
  * our dedicated function is more precise as it uses the drive provided
  * cycle time value. We should probably fix this one to deal with that too...
  */
-static int
-pmac_ide_tune_chipset (ide_drive_t *drive, byte speed)
+static int pmac_ide_tune_chipset(ide_drive_t *drive, const u8 speed)
 {
 	int unit = (drive->select.b.unit & 0x01);
 	int ret = 0;
 	pmac_ide_hwif_t* pmif = (pmac_ide_hwif_t *)HWIF(drive)->hwif_data;
 	u32 *timings, *timings2;
 
-	speed = ide_rate_filter(drive, speed);
-
 	if (pmif == NULL)
 		return 1;