au1xxx-ide: use hwif->dev

* Setup hwif->dev in au_ide_probe().

* Use hwif->dev instead of ahwif->dev in auide_build_sglist(),
  auide_build_dmatable(), auide_dma_end() and auide_ddma_init().

* Remove no longer needed 'dev' field from _auide_hwif type.

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