staging: comedi: amplc_dio200_common: convert driver to use the comedi_8254 module

Convert this driver to use the comedi_8254 module to provide the 8254 timer support.

Add 'clock_src' and 'gate_src' members to the comedi_8254 data for convienence.

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>