staging: comedi: das_08: unwind the 8254 timer support

Refactor the 8254 timer support by removing the various functions
that handle the io and consolidating the logic into the initialize,
read, write, and config functions used by the driver.

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>