ide: make ide_hwif_t.ide_dma_{host_off,off_quietly} void (v2)

* since ide_hwif_t.ide_dma_{host_off,off_quietly} always return '0'
  make these functions void and while at it drop "ide_" prefix
* fix comment for __ide_dma_off_quietly()
* make __ide_dma_{host_off,off_quietly,off}() void and drop "__" prefix

v2:
* while at it rename atiixp_ide_dma_host_off() to atiixp_dma_host_off(),
  sgiioc4_ide_dma_{host_off,off_quietly}() to sgiioc4_dma_{host_off,off_quietly}()
  and sl82c105_ide_dma_off_quietly() to sl82c105_dma_off_quietly()
  [ Noticed by Sergei Shtylyov <sshtylyov@ru.mvista.com>. ]

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

drivers/ide/pci/cs5530.c

@@ -109,7 +109,7 @@ static int cs5530_config_dma (ide_drive_t *drive)
 	/*
 	 * Default to DMA-off in case we run into trouble here.
 	 */
-	hwif->ide_dma_off_quietly(drive);
+	hwif->dma_off_quietly(drive);
 
 	/*
 	 * The CS5530 specifies that two drives sharing a cable cannot