ide: add ide_use_fast_pio() helper (v3)

* add ide_use_fast_pio() helper for use by host drivers

* add DMA capability and hwif->autodma checks to ide_use_dma()

  - au1xxx-ide/it8213/it821x drivers didn't check for (id->capability & 1)

    [ for the IT8211/2 in SMART mode this check shouldn't be made but since
      in it821x_fixups() we set DMA bit explicitly:

               if(strstr(id->model, "Integrated Technology Express")) {
                       /* In raid mode the ident block is slightly buggy
                          We need to set the bits so that the IDE layer knows
                          LBA28. LBA48 and DMA ar valid */
                       id->capability |= 3;            /* LBA28, DMA */

       we are better off using generic helper if we can ]

  - ide-cris driver didn't set ->autodma

    [ before the patch hwif->autodma was only checked in the chipset specific
      hwif->ide_dma_check implementations, for ide-cris it is cris_dma_check()
      function so there no behavior change here ]

v2:
* updated patch description (thanks to Alan Cox for the feedback)

v3:
* updated for scc_pata driver

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/pci/triflex.c

@@ -114,14 +114,9 @@ static int triflex_config_drive_for_dma(ide_drive_t *drive)
 static int triflex_config_drive_xfer_rate(ide_drive_t *drive)
 {
 	ide_hwif_t *hwif	= HWIF(drive);
-	struct hd_driveid *id	= drive->id;
 
-	if ((id->capability & 1) && drive->autodma) {
-		if (ide_use_dma(drive)) {
-			if (triflex_config_drive_for_dma(drive))
-				return hwif->ide_dma_on(drive);
-		}
-	}
+	if (ide_use_dma(drive) && triflex_config_drive_for_dma(drive))
+		return hwif->ide_dma_on(drive);
 
 	hwif->tuneproc(drive, 255);
 	return hwif->ide_dma_off_quietly(drive);