CGBASupport: Add Shutdown function

Runtime/MP1/CGBASupport.cpp

@@ -18,6 +18,10 @@ void CGBASupport::Initialize() {
   g_JbusListener.start();
 }
 
+void CGBASupport::Shutdown() {
+  g_JbusListener.stop();
+}
+
 void CGBASupport::GlobalPoll() {
   if (g_JbusEndpoint && !g_JbusEndpoint->connected())
     g_JbusEndpoint.reset();

Runtime/MP1/CGBASupport.hpp

@@ -36,6 +36,7 @@ private:
 
 public:
   static void Initialize();
+  static void Shutdown();
   static void GlobalPoll();
 
   CGBASupport();

Runtime/MP1/MP1.cpp

@@ -926,6 +926,7 @@ void CMain::ShutdownSubsystems() {
   CAnimData::FreeCache();
   CMemoryCardSys::Shutdown();
   CMappableObject::Shutdown();
+  CGBASupport::Shutdown();
 }
 
 void CMain::Shutdown() {