qtnfmac: fix invalid channel information output

Do not attempt to print frequency for an invalid channel
provided by firmware. That channel may simply not exist.
Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/quantenna/qtnfmac/event.c

@@ -171,8 +171,9 @@ qtnf_event_handle_bss_join(struct qtnf_vif *vif,
 		return -EPROTO;
 	}
 
-	pr_debug("VIF%u.%u: BSSID:%pM status:%u\n",
-		 vif->mac->macid, vif->vifid, join_info->bssid, status);
+	pr_debug("VIF%u.%u: BSSID:%pM chan:%u status:%u\n",
+		 vif->mac->macid, vif->vifid, join_info->bssid,
+		 le16_to_cpu(join_info->chan.chan.center_freq), status);
 
 	if (status != WLAN_STATUS_SUCCESS)
 		goto done;
@@ -181,7 +182,7 @@ qtnf_event_handle_bss_join(struct qtnf_vif *vif,
 	if (!cfg80211_chandef_valid(&chandef)) {
 		pr_warn("MAC%u.%u: bad channel freq=%u cf1=%u cf2=%u bw=%u\n",
 			vif->mac->macid, vif->vifid,
-			chandef.chan->center_freq,
+			chandef.chan ? chandef.chan->center_freq : 0,
 			chandef.center_freq1,
 			chandef.center_freq2,
 			chandef.width);