staging: comedi: adl_pci9118: tidy up start_pacer()

For aesthetics, rename this function so it has namespace associated
with the driver.

The divisors used to load the counters are stored in the private data.
Get them from there and remove the parameters.

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>