CPU features are available on ARM only wherever the
query-cpu-model-expansion QMP command is available, same as
on s390. Update qemuBuildCpuModelArgStr() to reflect this
fact.
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>
Tested-by: NAndrew Jones <drjones@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>