ide-tape: add ide_tape_io_buffers() helper

* Add ide_tape_io_buffers() helper which is a wrapper for
  idetape_{in,out}put_buffers() and convert idetape_pc_intr()
  to use it.

* Remove no longer used idetape_io_buf typedef.

There should be no functional changes caused by this patch.

Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>---