ide: unexport ide_set_xfer_rate() (v2)

In cmd64x, siimage and scc_pata drivers:
* don't set drive->init_speed as it should be already
  set by successful execution of ide_set_xfer_rate()
* use hwif->speedproc functions directly

Above changes allows removal of EXPORT_SYMBOL_GPL(ide_set_xfer_rate).

v2:
* updated for scc_pata driver

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

diff --git a/drivers/ide/pci/cmd64x.c b/drivers/ide/pci/cmd64x.c
index aee947e..009fc91 100644
--- a/drivers/ide/pci/cmd64x.c
+++ b/drivers/ide/pci/cmd64x.c
@@ -466,11 +466,8 @@
 	if (!speed)
 		return 0;
 
-	if(ide_set_xfer_rate(drive, speed))
-		return 0; 
-
-	if (!drive->init_speed)
-		drive->init_speed = speed;
+	if (cmd64x_tune_chipset(drive, speed))
+		return 0;
 
 	return ide_dma_enable(drive);
 }