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/cs5530.c

@@ -104,24 +104,6 @@ out:
 	return mask;
 }
 
-/**
- *	cs5530_config_dma	-	set DMA/UDMA mode
- *	@drive: drive to tune
- *
- *	cs5530_config_dma() handles setting of DMA/UDMA mode
- *	for both the chipset and drive.
- */
-
-static int cs5530_config_dma(ide_drive_t *drive)
-{
-	if (ide_tune_dma(drive))
-		return 0;
-
-	ide_set_max_pio(drive);
-
-	return -1;
-}
-
 static void cs5530_set_dma_mode(ide_drive_t *drive, const u8 mode)
 {
 	unsigned long basereg;
@@ -288,7 +270,7 @@ static void __devinit init_hwif_cs5530 (ide_hwif_t *hwif)
 	hwif->mwdma_mask = 0x07;
 
 	hwif->udma_filter = cs5530_udma_filter;
-	hwif->ide_dma_check = &cs5530_config_dma;
+
 	if (!noautodma)
 		hwif->autodma = 1;
 	hwif->drives[0].autodma = hwif->autodma;