Staging: comedi: add missing KERN_INFO in ni_at_ao.c

This is a patch to the ni_at_ao.c file that adds the missing
KERN_INFO requested by the checkpatch.pl tool.

Signed-off-by: Stewart Robertson <stewart_r@aliencamel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>