Some rare races between ide-default and ide-disk are possible, i.e.:
* ide-default is used, I/O request is triggered (ie. /proc/ide/hd?/identify),
  drive->special is cleared silently (so CHS is not initialized properly),
  ide-disk is loaded and fails if drive uses CHS
* ide-disk is used, drive is resetted, ide-disk is unloaded, ide-default
  takes control over drive and on the first I/O request silently clears
  drive->special without restoring settings

Fix them by moving idedisk_{special,pre_reset}() and company to IDE core.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>