staging: comedi: dt282x: refactor dt282x_ns_to_timer()

Define the pacer clock limits and remove the magic numbers. Refactor
the code to use a common path to return the actual 'ns' timing and
the timer divisor value.

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>
1 file changed