vfs: move mnt_mountpoint to struct mount

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/mount.h b/fs/mount.h
index 201dd61..853738f 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -3,6 +3,7 @@
 struct mount {
 	struct list_head mnt_hash;
 	struct mount *mnt_parent;
+	struct dentry *mnt_mountpoint;
 	struct vfsmount mnt;
 };