staging: comedi: das08: use better MODULE_DESCRIPTION()

Replace the boiler-plate Comedi module description string with something
more specific.

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