staging: comedi: me4000: use the 8253 helper functions

The counter subdevice of this board is a standard 8254 compatible
counter/timer. Instead of open-coding the 8254 timer io, use the
helper functions provided by 8253.h.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>