staging: comedi: addi_common.c: remove addi_auto_attach()

The addi_apci_035 and addi_apci_1500 are the only drivers left that use
this function in addi_common.c. The addi_common code adds a lot of bloat
to the drivers.

Copy the addi_auto_attach() code to the (*auto_attach) functions of the
drivers and remove the function. This will help with removing the bloat.

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>