staging: comedi: addi_apci_1564: enable support for PLD Rev 1.0 I/O mapping

Remove the error return in the (*auto_attach) and allow the driver to
attach to APC-1564 boards that use the PLD Rev 1.0 I/O mapping.

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>