aufs: built it on RT

[Stephen Hemminger <shemminger@vyatta.com>]

commit 485dd27c0ed3cfc553ef380a370c9614559aae08
Author: Stephen Hemminger <stephen.hemminger@vyatta.com>
Date:   Fri Oct 31 14:16:50 2008 -0700

    Fix aufs for -rt
    
    Rt changes some inode infrastructure to percpu.

diff --git a/fs/aufs/branch.c b/fs/aufs/branch.c
index e40ebcd..b52b085 100644
--- a/fs/aufs/branch.c
+++ b/fs/aufs/branch.c
@@ -898,7 +898,7 @@ static int au_br_mod_files_ro(struct super_block *sb, aufs_bindex_t bindex)
 
 	/* no need file_list_lock() since sbinfo is locked */
 	err = 0;
-	list_for_each_entry(file, &sb->s_files, f_u.fu_list) {
+	list_for_each_entry(file, percpu_list_head(&sb->s_files), f_u.fu_llist) {
 		LKTRTrace("%.*s\n", AuDLNPair(file->f_dentry));
 		if (!au_test_aufs_file(file))
 			continue;