staging: comedi: addi_apci_1516: final cleanup of the register map defines

I finally got hold of the i/o mapping from ADDI-DATA. Cleanup the defines
a bit and add the missing information.

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>