ide: set hwif->expiry prior to calling [__]ide_set_handler()

* Set hwif->expiry prior to calling [__]ide_set_handler()
  and drop 'expiry' argument.

* Set hwif->expiry to NULL in ide_{timer_expiry,intr}()
  and remove 'hwif->expiry = NULL' assignments.

There should be no functional changes caused by this patch.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>