Clean up the pending PKEX exchange if Commit-Reveal Request processing
indicates a mismatch in the PKEX code. Previously, the this case was
silently ignored and the session was left in pending state that
prevented new PKEX exchanges from getting initated. Now, a new attempt
is allowed to be initiated.
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>