Fix warning in Vehicle HAL

Test: mm -j

Change-Id: Ifc0654e912f3b592af90246af6d87324c469a8d3
Fix: b/34901911
diff --git a/automotive/vehicle/2.0/default/tests/VehicleHalTestUtils.h b/automotive/vehicle/2.0/default/tests/VehicleHalTestUtils.h
index a512fcf..8ba36d8 100644
--- a/automotive/vehicle/2.0/default/tests/VehicleHalTestUtils.h
+++ b/automotive/vehicle/2.0/default/tests/VehicleHalTestUtils.h
@@ -131,12 +131,12 @@
         mEventCond.notify_one();
         return Return<void>();
     }
-    Return<void> onPropertySet(const VehiclePropValue& value) override {
+    Return<void> onPropertySet(const VehiclePropValue& /* value */) override {
         return Return<void>();
     }
-    Return<void> onPropertySetError(StatusCode errorCode,
-                                    int32_t propId,
-                                    int32_t areaId) override {
+    Return<void> onPropertySetError(StatusCode /* errorCode */,
+                                    int32_t /* propId */,
+                                    int32_t /* areaId */) override {
         return Return<void>();
     }