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/pci/it8213.c

@@ -157,33 +157,11 @@ static void it8213_set_dma_mode(ide_drive_t *drive, const u8 speed)
 	it8213_set_pio_mode(drive, pio);
 }
 
-/**
- *	it8213_configure_drive_for_dma	-	set up for DMA transfers
- *	@drive: drive we are going to set up
- *
- *	Set up the drive for DMA, tune the controller and drive as
- *	required. If the drive isn't suitable for DMA or we hit
- *	other problems then we will drop down to PIO and set up
- *	PIO appropriately
- */
-
-static int it8213_config_drive_for_dma (ide_drive_t *drive)
-{
-	if (ide_tune_dma(drive))
-		return 0;
-
-	ide_set_max_pio(drive);
-
-	return -1;
-}
-
 /**
  *	init_hwif_it8213	-	set up hwif structs
  *	@hwif: interface to set up
  *
- *	We do the basic set up of the interface structure. The IT8212
- *	requires several custom handlers so we override the default
- *	ide DMA handlers appropriately
+ *	We do the basic set up of the interface structure.
  */
 
 static void __devinit init_hwif_it8213(ide_hwif_t *hwif)
@@ -208,8 +186,6 @@ static void __devinit init_hwif_it8213(ide_hwif_t *hwif)
 
 	pci_read_config_byte(hwif->pci_dev, 0x42, &reg42h);
 
-	hwif->ide_dma_check = &it8213_config_drive_for_dma;
-
 	if (hwif->cbl != ATA_CBL_PATA40_SHORT)
 		hwif->cbl = (reg42h & 0x02) ? ATA_CBL_PATA40 : ATA_CBL_PATA80;