nfsd: constify reply_cache_stats_operations structure

reply_cache_stats_operations, of type struct file_operations, is never
modified, so declare it as const.

Done with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfsctl.c

@@ -217,7 +217,7 @@ static const struct file_operations pool_stats_operations = {
 	.release	= nfsd_pool_stats_release,
 };
 
-static struct file_operations reply_cache_stats_operations = {
+static const struct file_operations reply_cache_stats_operations = {
 	.open		= nfsd_reply_cache_stats_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,