mka: Avoid memory leak in unexpected case in RECEIVE

mka: Avoid memory leak in unexpected case in RECEIVE

It looks like it is possible for the RECEIVE state to leak memory where
a previously allocated sm->lki is moved to sm->oki while sm->oki is
pointing to not yet freed entry. It is not clear how this can be
triggered, but it has come up in hwsim testing under heavy load.

Free sm->oki if it is still set in RECEIVE before replacing it with
sm->lki to avoid this memory leak.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>