staging: lustre: Use const static file_operations struct

This commit corrects the following sparse warning regarding a
file_operations structure being non-static and constifies the
structure in question as well.

  warning: symbol 'lprocfs_stats_seq_fops' was not declared.
    Should it be static?
Signed-off-by: M. Vefa Bicakci <m.v.b@runbox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/obdclass/lprocfs_status.c

@@ -1197,7 +1197,7 @@ static int lprocfs_stats_seq_open(struct inode *inode, struct file *file)
 	return 0;
 }
 
-struct file_operations lprocfs_stats_seq_fops = {
+static const struct file_operations lprocfs_stats_seq_fops = {
 	.owner   = THIS_MODULE,
 	.open    = lprocfs_stats_seq_open,
 	.read    = seq_read,