vfs: add flags to d_real()

Add a separate flags argument (in addition to the open flags) to control
the behavior of d_real().

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Documentation/filesystems/vfs.txt

@@ -990,7 +990,7 @@ struct dentry_operations {
 	struct vfsmount *(*d_automount)(struct path *);
 	int (*d_manage)(const struct path *, bool);
 	struct dentry *(*d_real)(struct dentry *, const struct inode *,
-				 unsigned int);
+				 unsigned int, unsigned int);
 };
 
   d_revalidate: called when the VFS needs to revalidate a dentry. This