The power state spec section 5.1.5 AFFINITY_INFO defines the
affinity info return values as

  0 ON
  1 OFF
  2 ON_PENDING

I grepped QEMU for power_state to ensure that no assumptions
of OFF=0 were being made.
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Message-id: 20170303123232.4967-1-drjones@redhat.com
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>