qcacld-3.0: Fix NULL pointer de-reference in wma functions

Add null pointer check after malloc/utility function call in function:
 * wma_update_tdls_peer_state
 * wma_init_max_no_of_peers
 * wma_mgmt_tx_completion_handler
 * wma_ocb_set_config
 * wma_roam_scan_offload_chan_list
 * wma_roam_scan_filter
 * wma_pno_start
 * wma_start_extscan

Change-Id: I3c46ffe19e98146a5e96781a88295af88274a74f
CRs-Fixed: 1034255
diff --git a/core/wma/src/wma_mgmt.c b/core/wma/src/wma_mgmt.c
index 5d0020e..302c17e 100644
--- a/core/wma/src/wma_mgmt.c
+++ b/core/wma/src/wma_mgmt.c
@@ -2463,9 +2463,14 @@
 
 	ol_txrx_pdev_handle pdev = cds_get_context(QDF_MODULE_ID_TXRX);
 
+	if (pdev == NULL) {
+		WMA_LOGE("%s: NULL pdev pointer", __func__);
+		return -EINVAL;
+	}
+
 	param_buf = (WMI_MGMT_TX_COMPLETION_EVENTID_param_tlvs *)
 		cmpl_event_params;
-	if (!param_buf && !wma_handle) {
+	if (!param_buf || !wma_handle) {
 		WMA_LOGE("%s: Invalid mgmt Tx completion event", __func__);
 		return -EINVAL;
 	}