staging: comedi: addi_apci_1564: remove unnecessary wdog register defines

The watchdog subdevice is supported using the addi_watchdog module and
it uses the register defines from addi_tcw.h. The only register define
needed it the iobase offset to the register block.

Remove the unnecessary defines and rename the iobase define.

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>