intel_iommu: Fix flag check in replay

Replay doesn't notify registered notifiers but the one passed
to it. So it's meaningless to check the registered notifier's
synthetic flag.

There is no issue currently as all replay use cases have MAP
flag set, but let's be robust.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20230615032626.314476-3-zhenzhong.duan@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>