Revert "SDL: handle SDL_QUIT event"

Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp

@@ -134,11 +134,6 @@ void ControllerInterface::Shutdown()
 //
 void ControllerInterface::UpdateInput()
 {
-#ifdef CIFACE_USE_SDL
-	// SDL currently also handles SIGINT and SIGTERM,
-	// so make sure to update it even if there is no SDL device.
-	ciface::SDL::UpdateInput();
-#endif
 	for (ciface::Core::Device* d : m_devices)
 		d->UpdateInput();
 }