Make LazyServiceRegistrar constructor private

This completes converting LazyServiceRegistrar into a singleton.

Test: lshal
Bug: 139376253
Change-Id: I3128921e0bc6674dc8bdce23380c86742f732bb4
diff --git a/transport/include/hidl/HidlLazyUtils.h b/transport/include/hidl/HidlLazyUtils.h
index 257de98..6a62c97 100644
--- a/transport/include/hidl/HidlLazyUtils.h
+++ b/transport/include/hidl/HidlLazyUtils.h
@@ -29,13 +29,13 @@
 /** Exits when all HALs registered through this object have 0 clients */
 class LazyServiceRegistrar {
    public:
-     LazyServiceRegistrar();
      static LazyServiceRegistrar& getInstance();
      status_t registerService(const sp<::android::hidl::base::V1_0::IBase>& service,
                               const std::string& name = "default");
 
    private:
      std::shared_ptr<details::LazyServiceRegistrarImpl> mImpl;
+     LazyServiceRegistrar();
 };
 
 }  // namespace hardware