ide: (hopefully) fix VDMA for CS5520

* Set the correct hwif->dma_base for the second channel in
  ide_get_or_set_dma_base().

* Remove DMA enable code from cs5520_set_pio_mode(), this can
  be handled by the generic ->dma_host_on method now.

* Add VDMA check to ide_config_drive_speed().

* drive->using_dma was never enabled since cs5520 host driver's
  ->ide_dma_on method overrided the generic ->ide_dma_on (so
  __ide_dma_on() was never called, drive->using_dma was never set
  and VDMA was never used since it depends on drive->using_dma).

  Fix it by using ->dma_host_on method instead of ->ide_dma_on
  (also add matching ->dma_host_off method).

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-iops.c b/drivers/ide/ide-iops.c
index c97c071..e3e5e39 100644
--- a/drivers/ide/ide-iops.c
+++ b/drivers/ide/ide-iops.c
@@ -799,7 +799,7 @@
 
  skip:
 #ifdef CONFIG_BLK_DEV_IDEDMA
-	if (speed >= XFER_SW_DMA_0)
+	if (speed >= XFER_SW_DMA_0 || (hwif->host_flags & IDE_HFLAG_VDMA))
 		hwif->dma_host_on(drive);
 	else if (hwif->ide_dma_on)	/* check if host supports DMA */
 		hwif->dma_off_quietly(drive);