Staging: comedi: addi-data: tidy up watchdog register

This patch for fixes the register map defines for the watchdog registers
such that they are all the real offsets to each register, rather than a
mix of real offsets and adders to those offsets.

Signed-off-by: Chase Southwood <chase.southwood@yahoo.com>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>