ide: make ide_hwif_t.ide_dma_host_on void (v2)

* since ide_hwif_t.ide_dma_host_on is called either when drive->using_dma == 1
  or when return value is discarded make it void, also drop "ide_" prefix
* make __ide_dma_host_on() void and drop "__" prefix

v2:
* while at it rename atiixp_ide_dma_host_on() to atiixp_dma_host_on()
  and sgiioc4_ide_dma_host_on() to sgiioc4_dma_host_on().
  [ Noticed by Sergei Shtylyov <sshtylyov@ru.mvista.com>. ]

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

diff --git a/drivers/ide/pci/sgiioc4.c b/drivers/ide/pci/sgiioc4.c
index d9aa200..fd09b29 100644
--- a/drivers/ide/pci/sgiioc4.c
+++ b/drivers/ide/pci/sgiioc4.c
@@ -279,7 +279,7 @@
 {
 	drive->using_dma = 1;
 
-	return HWIF(drive)->ide_dma_host_on(drive);
+	return 0;
 }
 
 static void sgiioc4_dma_off_quietly(ide_drive_t *drive)
@@ -307,13 +307,8 @@
 	return sgiioc4_checkirq(HWIF(drive));
 }
 
-static int
-sgiioc4_ide_dma_host_on(ide_drive_t * drive)
+static void sgiioc4_dma_host_on(ide_drive_t * drive)
 {
-	if (drive->using_dma)
-		return 0;
-
-	return 1;
 }
 
 static void sgiioc4_dma_host_off(ide_drive_t * drive)
@@ -610,7 +605,7 @@
 	hwif->ide_dma_on = &sgiioc4_ide_dma_on;
 	hwif->dma_off_quietly = &sgiioc4_dma_off_quietly;
 	hwif->ide_dma_test_irq = &sgiioc4_ide_dma_test_irq;
-	hwif->ide_dma_host_on = &sgiioc4_ide_dma_host_on;
+	hwif->dma_host_on = &sgiioc4_dma_host_on;
 	hwif->dma_host_off = &sgiioc4_dma_host_off;
 	hwif->ide_dma_lostirq = &sgiioc4_ide_dma_lostirq;
 	hwif->ide_dma_timeout = &__ide_dma_timeout;