staging: comedi: das16m1: convert driver to use the comedi_8254 module

staging: comedi: das16m1: convert driver to use the comedi_8254 module

This driver uses two 8254 timers. One to generate the analog input pacer clock and
one to count the number of samples. Convert it to use the comedi_8254 module to
provide support for the 8254 timers.

Use the comedi_device 'pacer' member for the 8254 timer used for analog input. This
data is freed automatically by the core during the detach of the driver.

Store the data for the 8254 timer used to count samples in the private data. This
data needs to be freed by the driver when it is detached.

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>