staging: comedi: addi_apci_1032: remove len_chanlist on di subdevice

This value is only needed for subdevices that support async commands.
The comedi core will default the value to 1 when it is not initialized.

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