Convert LazyServiceRegistrar usage to singleton

Test: lshal
Bug: 139376253
Change-Id: Ib1cbfabec23a488868e807a4a9c2b29cd960cc1e
diff --git a/cas/1.0/default/service.cpp b/cas/1.0/default/service.cpp
index 516acfb..754c0c5 100644
--- a/cas/1.0/default/service.cpp
+++ b/cas/1.0/default/service.cpp
@@ -46,8 +46,8 @@
     android::sp<IMediaCasService> service = new MediaCasService();
     android::status_t status;
     if (kLazyService) {
-        auto serviceRegistrar = std::make_shared<LazyServiceRegistrar>();
-        status = serviceRegistrar->registerService(service);
+        auto serviceRegistrar = LazyServiceRegistrar::getInstance();
+        status = serviceRegistrar.registerService(service);
     } else {
         status = service->registerAsService();
     }