staging: comedi: adl_pci9118: remove 'ai_pacer_min' from boardinfo

This value can easily be calculated based on the minimum sampling rate,
'ai_ns_min', and the base clock speed of the timers. Do that instead and
remove the boardinfo.

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>