ath9k: Clear key cache explicitly on disabling hardware

Now that ath/key.c may not be explicitly clearing keys from the key
cache, clear all key cache entries when disabling hardware to make sure
no keys are left behind beyond this point.
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201214172118.18100-3-jouni@codeaurora.org

drivers/net/wireless/ath/ath9k/main.c

@@ -894,6 +894,11 @@ static void ath9k_stop(struct ieee80211_hw *hw)
 
 	spin_unlock_bh(&sc->sc_pcu_lock);
 
+	/* Clear key cache entries explicitly to get rid of any potentially
+	 * remaining keys.
+	 */
+	ath9k_cmn_init_crypto(sc->sc_ah);
+
 	ath9k_ps_restore(sc);
 
 	sc->ps_idle = prev_idle;