Convert LazyServiceRegistrar usage to singleton

Test: lshal
Bug: 139376253
Change-Id: I32cb803fb73aa15b52676847b6e7eb09b86657dc
diff --git a/cas/1.1/default/service.cpp b/cas/1.1/default/service.cpp
index 9625303..bf0e159 100644
--- a/cas/1.1/default/service.cpp
+++ b/cas/1.1/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();
     }