qcacld-3.0: Correct NULL check when using ol_tx_dest_addr_find

Fix static analyze issues. add NULL pointer check.

Change-Id: Icc80211b945d1eaabfb6015ba93e0c3114f2c589
CRs-Fixed: 2059683

core/dp/txrx/ol_tx_classify.c

@@ -397,6 +397,12 @@ ol_tx_classify(
 
 	TX_SCHED_DEBUG_PRINT("Enter %s\n", __func__);
 	dest_addr = ol_tx_dest_addr_find(pdev, tx_nbuf);
+	if (unlikely(NULL == dest_addr)) {
+		QDF_TRACE(QDF_MODULE_ID_TXRX,
+				QDF_TRACE_LEVEL_ERROR,
+				"Error: dest_addr is NULL.\n");
+		return NULL; /*error*/
+	}
 	if ((IEEE80211_IS_MULTICAST(dest_addr)) ||
 	    (vdev->opmode == wlan_op_mode_ocb)) {
 		txq = &vdev->txqs[OL_TX_VDEV_MCAST_BCAST];
@@ -629,6 +635,12 @@ ol_tx_classify_mgmt(
 
 	TX_SCHED_DEBUG_PRINT("Enter %s\n", __func__);
 	dest_addr = ol_tx_dest_addr_find(pdev, tx_nbuf);
+	if (unlikely(NULL == dest_addr)) {
+		QDF_TRACE(QDF_MODULE_ID_TXRX,
+				QDF_TRACE_LEVEL_ERROR,
+				"Error: dest_addr is NULL.\n");
+		return NULL; /*error*/
+	}
 	if (IEEE80211_IS_MULTICAST(dest_addr)) {
 		/*
 		 * AP:  beacons are broadcast,