DPP2: Accept Config Result before GAS response TX status

DPP2: Accept Config Result before GAS response TX status

The TX event for the next frame in the sequence might be received before
the TX status for the final GAS response frame is processed. This used
to result in the Config Result getting discarded and the negotiation not
completing successfully on the Configurator side.

Accept the Config Result message as an indication of the final GAS
response frame having went through fine even if the TX status has not
yet been processed to avoid this issue from a potential race condition
on kernel events.

Signed-off-by: Jouni Malinen <j@w1.fi>