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/ppc/scc_pata.c b/drivers/ide/ppc/scc_pata.c
index 3993d08..65ad8ab3 100644
--- a/drivers/ide/ppc/scc_pata.c
+++ b/drivers/ide/ppc/scc_pata.c
@@ -363,12 +363,9 @@
 	if (!speed)
 		return 0;
 
-	if (ide_set_xfer_rate(drive, speed))
+	if (scc_tune_chipset(drive, speed))
 		return 0;
 
-	if (!drive->init_speed)
-		drive->init_speed = speed;
-
 	return ide_dma_enable(drive);
 }