staging: comedi: usbdux drivers: use comedi_dio_update_state()

Use comedi_dio_update_state() to handle the boilerplate code to update
the subdevice s->state.

These drivers always need to update the hardware in order to update
the i/o configuration regardless of if the state has changed.

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>