ide: add hwif->ack_intr hook

* Add hwif->ack_intr hook and use it instead of hwif->hw.ack_intr.

* Add missing brackets to cris-v32 and powerpc ide_ack_intr() macros.

Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>