staging: comedi: adl_pci9111: analog output subdevice is fixed

The analog output subdevice is the same for all boards supported
by this driver. Remove the boardinfo for it and just open-code
the values in the attach function.

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