The new interface can be used to replace the old notify_started() and
notify_stopped(). Meanwhile it provides explicit flags so that IOMMUs
can know what kind of notifications it is requested for.

Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1474606948-14391-3-git-send-email-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>