hw/i386/pc: enable PVH only for machine type >= 4.0

In order to avoid migration issues, we enable PVH only for
machine type >= 4.0

Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
4 files changed