qcacld-3.0: Add initialization value for mac_hdr pointer

Add initialization value for mac_hdr pointer in
function lim_deauth_tx_complete_cnf_handler().

Change-Id: I429e1a2cdad8a86907033719274def00acf7ff69
CRs-Fixed: 3626801

core/mac/src/pe/lim/lim_send_management_frames.c

@@ -4088,7 +4088,7 @@ static QDF_STATUS lim_deauth_tx_complete_cnf_handler(void *context,
 	struct scheduler_msg msg = {0};
 	tLimMlmDeauthReq *deauth_req;
 	struct pe_session *session = NULL;
-	tSirMacMgmtHdr *mac_hdr;
+	tSirMacMgmtHdr *mac_hdr = NULL;
 	uint8_t vdev_id = WLAN_INVALID_VDEV_ID;
 	struct wmi_mgmt_params *mgmt_params =
 			(struct wmi_mgmt_params *)params;