SAE: Update PT value at later point for SME cases, if needed

SAE: Update PT value at later point for SME cases, if needed

It was possible to hit a case where the SAE PT had not yet been derived,
e.g., when using P2P group re-invocation. Update PT use at the time
authentication is started, if needed, to avoid this. While this is not
really ideal from the externally observable timing view point, this is
done only for the case where there is no other option available with a
dynamically changing network configuration for P2P. Similar design was
already in place for the SAE offload-from-driver (external auth) case.

Signed-off-by: Jouni Malinen <quic_jouni@quicinc.com>