hle: service: sm: Improve Initialize implementation.

src/core/hle/service/sm/sm.cpp

@@ -107,6 +107,8 @@ SM::~SM() = default;
 void SM::Initialize(Kernel::HLERequestContext& ctx) {
     LOG_DEBUG(Service_SM, "called");
 
+    is_initialized = true;
+
     IPC::ResponseBuilder rb{ctx, 2};
     rb.Push(RESULT_SUCCESS);
 }

src/core/hle/service/sm/sm.h

@@ -44,6 +44,7 @@ private:
     void UnregisterService(Kernel::HLERequestContext& ctx);
 
     std::shared_ptr<ServiceManager> service_manager;
+    bool is_initialized{};
     Kernel::KernelCore& kernel;
 };