ide: remove ->ide_dma_check (take 2)

* Add IDE_HFLAG_TRUST_BIOS_FOR_DMA host flag for host drivers that depend
  on BIOS for programming device/controller for DMA.  Set it in cy82c693,
  generic, ns87415, opti621 and trm290 host drivers.

* Add IDE_HFLAG_VDMA host flag for host drivers using VDMA.  Set it in cs5520
  host driver.

* Teach ide_tune_dma() about IDE_HFLAG_TRUST_BIOS_FOR_DMA flag.

* Add generic ide_dma_check() helper and remove all open coded ->ide_dma_check
  implementations.  Fix all places checking for presence of ->ide_dma_check
  hook to check for ->ide_dma_on instead.

* Remove no longer needed code from config_drive_for_dma().

* Make ide_tune_dma() static.

v2:
* Fix config_drive_for_dma() return values.

* Fix ide-dma.c build for CONFIG_BLK_DEV_IDEDMA_PCI=n by adding
  dummy config_drive_for_dma() inline.

* Fix IDE_HFLAG_TRUST_BIOS_FOR_DMA handling in ide_dma_check().

* Fix init_hwif_it8213() comment.

There should be no functionality changes caused by this patch.

Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/arm/icside.c

@@ -309,14 +309,6 @@ static int icside_dma_on(ide_drive_t *drive)
 	return 0;
 }
 
-static int icside_dma_check(ide_drive_t *drive)
-{
-	if (ide_tune_dma(drive))
-		return 0;
-
-	return -1;
-}
-
 static int icside_dma_end(ide_drive_t *drive)
 {
 	ide_hwif_t *hwif = HWIF(drive);
@@ -434,7 +426,6 @@ static void icside_dma_init(ide_hwif_t *hwif)
 	hwif->set_dma_mode	= icside_set_dma_mode;
 	hwif->autodma		= 1;
 
-	hwif->ide_dma_check	= icside_dma_check;
 	hwif->dma_host_off	= icside_dma_host_off;
 	hwif->dma_off_quietly	= icside_dma_off_quietly;
 	hwif->dma_host_on	= icside_dma_host_on;