ide: remove ->ide_dma_on and ->dma_off_quietly methods from ide_hwif_t

* Make ide_dma_off_quietly() and __ide_dma_on() always available.

* Drop "__" prefix from __ide_dma_on().

* Check for presence of ->dma_host_on instead of ->ide_dma_on.

* Convert all users of ->ide_dma_on and ->dma_off_quietly methods
  to use ide_dma_on() and ide_dma_off_quietly() instead.

* Remove no longer needed ->ide_dma_on and ->dma_off_quietly methods
  from ide_hwif_t.

* Make ide_dma_on() void.

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/sc1200.c b/drivers/ide/pci/sc1200.c
index fef20bd..8a94c3e 100644
--- a/drivers/ide/pci/sc1200.c
+++ b/drivers/ide/pci/sc1200.c
@@ -220,7 +220,7 @@
 	}
 	if (mode != -1) {
 		printk("SC1200: %s: changing (U)DMA mode\n", drive->name);
-		hwif->dma_off_quietly(drive);
+		ide_dma_off_quietly(drive);
 		if (ide_set_dma_mode(drive, mode) == 0)
 			hwif->dma_host_on(drive);
 		return;