Bugfix: add "override" explicitly to make the compiler happy

Test: build

Bug: 148877226
Change-Id: I90806ee2c2302ce9cc5dc8f82754aa807c2ec7ef
diff --git a/automotive/vehicle/2.0/default/common/include/vhal_v2_0/VehicleObjectPool.h b/automotive/vehicle/2.0/default/common/include/vhal_v2_0/VehicleObjectPool.h
index e3cbf2e..f2d3c13 100644
--- a/automotive/vehicle/2.0/default/common/include/vhal_v2_0/VehicleObjectPool.h
+++ b/automotive/vehicle/2.0/default/common/include/vhal_v2_0/VehicleObjectPool.h
@@ -206,7 +206,7 @@
         InternalPool(VehiclePropertyType type, size_t vectorSize)
             : mPropType(type), mVectorSize(vectorSize) {}
 
-        RecyclableType obtain() {
+        RecyclableType obtain() override {
             return ObjectPool<VehiclePropValue>::obtain();
         }
     protected: