wlantest: Do not report decryption keys when checking only zero TK

All the "Failed to decrypt frame" debug prints were confusing since
those were not supposed to be shown unless there were one or more real
TKs available. The recently added check for zero TK added these notes
for that case which is not really correct, so get rid of them.

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

wlantest/rx_data.c

@@ -325,7 +325,7 @@ skip_replay_det:
 		write_pcap_decrypted(wt, (const u8 *) hdr, hdrlen,
 				     decrypted, dlen);
 	} else
-		add_note(wt, MSG_DEBUG, "Failed to decrypt frame");
+		add_note(wt, MSG_DEBUG, "Failed to decrypt frame (group)");
 	os_free(decrypted);
 }
 
@@ -348,6 +348,7 @@ static void rx_data_bss_prot(struct wlantest *wt,
 	int ptk_iter_done = 0;
 	int try_ptk_iter = 0;
 	int replay = 0;
+	int only_zero_tk = 0;
 
 	if (hdr->addr1[0] & 0x01) {
 		rx_data_bss_prot_group(wt, hdr, hdrlen, qos, dst, src,
@@ -427,6 +428,7 @@ static void rx_data_bss_prot(struct wlantest *wt,
 		if (dl_list_empty(&wt->ptk)) {
 			if (len >= 4 && sta) {
 				keyid = data[3] >> 6;
+				only_zero_tk = 1;
 				goto check_zero_tk;
 			}
 			return;
@@ -619,7 +621,7 @@ check_zero_tk:
 		write_pcap_decrypted(wt, (const u8 *) hdr, hdrlen,
 				     decrypted, dlen);
 	} else {
-		if (!try_ptk_iter)
+		if (!try_ptk_iter && !only_zero_tk)
 			add_note(wt, MSG_DEBUG, "Failed to decrypt frame");
 
 		/* Assume the frame was corrupted and there was no FCS to check.