qcacld-3.0: Fix roam Unit test command fail

Since fw update the logic of roam stats, the data of
wmi_roam_trigger_reason maybe null when fw send event
of WMI_ROAM_STATS_EVENTID to host driver, and at that
time, the num_roam_trigger_reason is zero, we don't
need reduce the length when extract roam stats event.

Change-Id: I332de7ba2d2efeba722e2194af4b9c97ef310a73
CRs-Fixed: 3475501

components/wmi/src/wmi_unified_roam_tlv.c

@@ -3036,6 +3036,7 @@ extract_roam_stats_event_tlv(wmi_unified_t wmi_handle, uint8_t *evt_buf,
 	struct roam_msg_info *roam_msg_info = NULL;
 	uint8_t vdev_id, i, num_btm = 0, num_frames = 0;
 	uint8_t num_tlv = 0, num_chan = 0, num_ap = 0, num_rpt = 0;
+	uint8_t num_trigger_reason = 0;
 	uint32_t rem_len;
 	QDF_STATUS status;
 
@@ -3064,13 +3065,18 @@ extract_roam_stats_event_tlv(wmi_unified_t wmi_handle, uint8_t *evt_buf,
 		num_tlv = MAX_ROAM_SCAN_STATS_TLV;
 	}
 
+	if (param_buf->roam_trigger_reason)
+		num_trigger_reason = num_tlv;
+	else
+		num_trigger_reason = 0;
+
 	rem_len = len - sizeof(*fixed_param);
-	if (rem_len < num_tlv * sizeof(wmi_roam_trigger_reason)) {
+	if (rem_len < num_trigger_reason * sizeof(wmi_roam_trigger_reason)) {
 		wmi_err_rl("Invalid roam trigger data");
 		return QDF_STATUS_E_INVAL;
 	}
 
-	rem_len -= num_tlv * sizeof(wmi_roam_trigger_reason);
+	rem_len -= num_trigger_reason * sizeof(wmi_roam_trigger_reason);
 	if (rem_len < num_tlv * sizeof(wmi_roam_scan_info)) {
 		wmi_err_rl("Invalid roam scan data");
 		return QDF_STATUS_E_INVAL;