* Add DMA blacklist checking (->ide_dma_on check probably can go now).

* Add ->atapi_dma flag checking and remove no longer needed
  ns87415_ide_dma_check() from ns87415 host driver.

* Remove now needless __ide_dma_check() wrapper and symbol export.

* Check drive->autodma instead of hwif->autodma (there should be no changes in
  behavior as all users of config_drive_for_dma() set both ->autodma flags).
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>