WPS: Fix clear-from-timeout handling to avoid race condition

WPS: Fix clear-from-timeout handling to avoid race condition

The 100 ms timeout to clear WPS state after EAP-Failure has been
received worked otherwise fine, but it opened a race condition on
another WPS operation starting within that wait. If that happens, the
timeout will cancel that new operation unexpectedly. Fix this by
cancelling the timeout from wpas_clear_wps().

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