staging: comedi: amplc_pc263: Change DIO subdevice to DO

This is a relay output card with no inputs.  It's single subdevice is
currently a digital input/output subdevice (COMEDI_SUBD_DIO).  It should
really be a digital output subdevice (COMEDI_SUBD_DO).  Change the
subdevice type and remove the insn_config() hook as it doesn't do
anything useful.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>