staging: comedi: addi_common.c: remove included source file

The addi_apci_035 and addi_apci_1500 are the only drivers left that
include this source file. Copy the i_ADDIDATA_InsnReadEeprom() function
from that file to those drivers and remove the addi_common.c file.

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>