mka: Fix use after free

We must cancel the timer when we delete an MKA instance.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>

src/pae/ieee802_1x_kay.c

@@ -3438,6 +3438,7 @@ ieee802_1x_kay_delete_mka(struct ieee802_1x_kay *kay, struct mka_key_name *ckn)
 		return;
 	}
 
+	eloop_cancel_timeout(ieee802_1x_participant_timer, participant, NULL);
 	dl_list_del(&participant->list);
 
 	/* remove live peer */