Including all machine types that might have a pcie-root-port.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Message-Id: <154394083644.28192.8501647946108201466.stgit@gimli.home>
Reviewed-by: NEric Auger <eric.auger@redhat.com>
[ehabkost: fixed accidental recursion at spapr_machine_3_1_class_options()]
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>