staging: comedi: ssv_dnp: use comedi_dio_update_state()

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

Also, fix a bug where the state of the channels is returned in data[0].
The comedi core expects it to be returned in data[1].

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>