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/ppc/pmac.c b/drivers/ide/ppc/pmac.c
index d3bb247..395d352 100644
--- a/drivers/ide/ppc/pmac.c
+++ b/drivers/ide/ppc/pmac.c
@@ -1983,10 +1983,8 @@
 {
 }
 
-static int
-pmac_ide_dma_host_on (ide_drive_t *drive)
+static int pmac_ide_dma_host_on(ide_drive_t *drive)
 {
-	return 0;
 }
 
 static int
@@ -2041,7 +2039,7 @@
 	hwif->ide_dma_end = &pmac_ide_dma_end;
 	hwif->ide_dma_test_irq = &pmac_ide_dma_test_irq;
 	hwif->dma_host_off = &pmac_ide_dma_host_off;
-	hwif->ide_dma_host_on = &pmac_ide_dma_host_on;
+	hwif->dma_host_on = &pmac_ide_dma_host_on;
 	hwif->ide_dma_timeout = &__ide_dma_timeout;
 	hwif->ide_dma_lostirq = &pmac_ide_dma_lostirq;