ide: remove ide_dma_enable()

* check ->speedproc return value in ide_tune_dma()
* use ide_tune_dma() in cmd64x/cs5530/sc1200/siimage/sl82c105/scc_pata drivers
* remove no longer needed ide_dma_enable()

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

drivers/ide/ide-dma.c

@@ -792,9 +792,10 @@ int ide_tune_dma(ide_drive_t *drive)
 	if (!speed)
 		return 0;
 
-	drive->hwif->speedproc(drive, speed);
+	if (drive->hwif->speedproc(drive, speed))
+		return 0;
 
-	return ide_dma_enable(drive);
+	return 1;
 }
 
 EXPORT_SYMBOL_GPL(ide_tune_dma);