qcacld-3.0: Prevent null pointer dereference issue

Add null check for pdev after cds_get_context, while
retrieving the context maintained by CDS

Change-Id: I2d6de7d5ad2a46139b2594cf966f2c083c9bb4b4
CRs-Fixed: 2187396

core/hdd/src/wlan_hdd_ipa.c

@@ -2650,6 +2650,11 @@ static void hdd_ipa_uc_op_cb(struct op_msg_type *op_msg, void *usr_ctxt)
 	struct ol_txrx_pdev_t *pdev = cds_get_context(QDF_MODULE_ID_TXRX);
 	QDF_STATUS status = QDF_STATUS_SUCCESS;
 
+	if (!pdev) {
+		HDD_IPA_LOG(QDF_TRACE_LEVEL_FATAL, "pdev is NULL");
+		return;
+	}
+
 	if (!op_msg || !usr_ctxt) {
 		HDD_IPA_LOG(QDF_TRACE_LEVEL_ERROR, "INVALID ARG");
 		return;