staging: comedi: adv_pci1710: convert driver to use the comedi_8254 module

This driver uses an 8254 timer to generate the pacer clock used for analog
input data acquisition. It also provides a comedi_subdevice to allow the user
to use channel 0 of the 8254 timer. Currently the subdevice support does not
work correctly due to and (*insn_config) that does not follow the comedi API.

Convert it to use the comedi_8254 module to provide support for the 8254 timer
and proper support for the subdevice.

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>