qcacld-3.0: Fix NULL pointer access in sme_set_wlm_latency_level

'wma' pointer is initialized using the return value of
cds_get_context;This function can return NULL value.

Check for NULL pointer before dereferencing the 'wma'.

Change-Id: I529a34fba91f19bdd6c62d14e97cfabb476cdf7f
CRs-Fixed: 2239647

core/sme/src/common/sme_api.c

@@ -8769,6 +8769,9 @@ QDF_STATUS sme_set_wlm_latency_level(tHalHandle hal, uint16_t session_id,
 	struct wlm_latency_level_param params;
 	void *wma = cds_get_context(QDF_MODULE_ID_WMA);
 
+	if (!wma)
+		return QDF_STATUS_E_FAILURE;
+
 	if (!mac_ctx->roam.configParam.wlm_latency_enable) {
 		QDF_TRACE(QDF_MODULE_ID_SME, QDF_TRACE_LEVEL_ERROR,
 			  "%s: WLM latency level setting is disabled",