staging: comedi: adv_pci1710: remove boardinfo 'rangelist_ao'

This boardinfo is not necessary. All the boards with analog outputs have
the same range options except for the pci1720 board. That board type is
already handled specially during the driver attach.

Remove the boardinfo and add the subdevice range_table initialization in
the cardtype switch.

Rename the range tables to clarify that they are "analog output" ranges.

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>