staging: comedi: addi-data: remove unused defines in addi_common.h

Due to the on-going cleanup of the addi-data drivers, there are a
number of unused defines in addi_common.h. Remove the cruft.

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>