ide: cleanup ide-dma.c

- s/HWIF(drive)/drive->hwif/
- s/HWGROUP(drive)/[drive->]hwif->hwgroup/
- fixup error messages in ide_dma_intr() & dma_timer_expiry()
- fix checkpatch.pl errors/warnings

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