ath9k: Do not indicate RX_FLAG_DECRYPTED for unprotected frames

mac80211 skips drop_unencrypted checks if the driver/firmware has
already taken care of this. In case of ath9k, we must not indicate
that the frame was decrypted if no decryption was actually done.
Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -255,7 +255,8 @@ void ath9k_cmn_rx_skb_postprocess(struct ath_common *common,
 
 	keyix = rx_stats->rs_keyix;
 
-	if (!(keyix == ATH9K_RXKEYIX_INVALID) && !decrypt_error) {
+	if (!(keyix == ATH9K_RXKEYIX_INVALID) && !decrypt_error &&
+	    ieee80211_has_protected(fc)) {
 		rxs->flag |= RX_FLAG_DECRYPTED;
 	} else if (ieee80211_has_protected(fc)
 		   && !decrypt_error && skb->len >= hdrlen + 4) {