According to the ISA the root page directory size of a radix tree for
either process- or partition-scoped translation must be >= 5.

Thus add this to the list of conditions checked when validating the
partition table entry in validate_pate();

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20200330094946.24678-2-clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>