ide: merge all TASKFILE_NO_DATA data phase handlers into taskfile_no_intr()

* Add 'struct task_s' to ide_hwif_t and init it to the current command
  in do_rw_taskfile().

* Merge all TASKFILE_NO_DATA data phase handlers into taskfile_no_intr().

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