staging: comedi: das16m1: use comedi_legacy_detach()

Use the new comedi_legacy_detach() helper in the (*detach) to release
the first I/O region requested by this driver.

An additional I/O region is requested by this driver for the 8255
device. Save the iobase for that region in the private data so that
the (*detach) knows it needs to be released.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>