fix a braino in ovl_d_select_inode()

commit 9391dd00 upstream.

when opening a directory we want the overlayfs inode, not one from
the topmost layer.

Reported-By: Andrey Jr. Melnikov <temnota.am@gmail.com>
Tested-By: Andrey Jr. Melnikov <temnota.am@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Kamata, Munehisa" <kamatam@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>