Right now it is possible to crash QEMU for s390x by providing e.g.
    -numa node,nodeid=0,cpus=0-1

Problem is, that numa.c uses mc->cpu_index_to_instance_props as an
indicator whether NUMA is supported by a machine type. We don't
implement NUMA for s390x ("topology") yet. However we need
mc->cpu_index_to_instance_props for query-cpus.

So let's fix this case by also checking for mc->get_default_cpu_node_id,
which will be needed by machine_set_cpu_numa_node().

qemu-system-s390x: -numa node,nodeid=0,cpus=0-1: NUMA is not supported by
                   this machine-type

While at it, make s390_cpu_index_to_props() look like on other
architectures.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180227110255.20999-1-david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>