Update IDE PMAC host driver to use drive->noprobe instead of hwif->noprobe
and remove hwif->noprobe completely (it is always set to zero now).

There should be no functional changes caused by this patch.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>