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/siimage.c b/drivers/ide/pci/siimage.c
index 50f6d17..4c1f3bc 100644
--- a/drivers/ide/pci/siimage.c
+++ b/drivers/ide/pci/siimage.c
@@ -229,14 +229,12 @@
 /**
  *	siimage_tune_chipset	-	set controller timings
  *	@drive: Drive to set up
- *	@xferspeed: speed we want to achieve
+ *	@speed: speed we want to achieve
  *
- *	Tune the SII chipset for the desired mode. If we can't achieve
- *	the desired mode then tune for a lower one, but ultimately
- *	make the thing work.
+ *	Tune the SII chipset for the desired mode.
  */
- 
-static int siimage_tune_chipset (ide_drive_t *drive, byte xferspeed)
+
+static int siimage_tune_chipset(ide_drive_t *drive, const u8 speed)
 {
 	u8 ultra6[]		= { 0x0F, 0x0B, 0x07, 0x05, 0x03, 0x02, 0x01 };
 	u8 ultra5[]		= { 0x0C, 0x07, 0x05, 0x04, 0x02, 0x01 };
@@ -245,7 +243,6 @@
 	ide_hwif_t *hwif	= HWIF(drive);
 	u16 ultra = 0, multi	= 0;
 	u8 mode = 0, unit	= drive->select.b.unit;
-	u8 speed		= ide_rate_filter(drive, xferspeed);
 	unsigned long base	= (unsigned long)hwif->hwif_data;
 	u8 scsc = 0, addr_mask	= ((hwif->channel) ?
 				    ((hwif->mmio) ? 0xF4 : 0x84) :