staging: comedi: addi_common.h: cleanup after removal of addi_apci_1710

Now that the addi_apci_1710 driver has been removed, get rid of all the
unnecessary stuff in addi_common.h.

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>