ocfs2: Silence false lockdep warnings

Create separate lockdep lock classes for system file's i_mutexes. They are
used to guard allocations and similar things and thus rank differently
than i_mutex of a regular file or directory.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 74018ca..ae9ad95 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -128,7 +128,7 @@
 	if (status < 0)
 		goto bail_add;
 
-	inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0);
+	inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0);
 	if (IS_ERR(inode)) {
 		ret = ERR_PTR(-EACCES);
 		goto bail_unlock;