staging: dgrp: cleanup sparse warnings

A cleanup patch to remove sparse warnings caused by my other patch
"procfs: Improve Scaling in proc" since now proc_fops is protected by the rcu.

Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Cc: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>