staging: comedi: addi_apci_all.c: remove unused file

The Makefile for the comedi subsystem does not compile this file
for any .config selection. This file would allow building one big
driver to support all the addi-data cards.

The addi-data drivers are a big enough mess as-is. Just remove this
file.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Iam Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>