Core: Move Emulation IOS instance to System.

Source/Core/Core/System.h

@@ -53,6 +53,10 @@ namespace GPFifo
 {
 class GPFifoManager;
 }
+namespace IOS::HLE
+{
+class EmulationKernel;
+}
 namespace HSP
 {
 class HSPManager;
@@ -148,6 +152,9 @@ public:
   bool IsAudioDumpStarted() const;
   void SetAudioDumpStarted(bool started);
 
+  IOS::HLE::EmulationKernel* GetIOS() const;
+  void SetIOS(std::unique_ptr<IOS::HLE::EmulationKernel> ios);
+
   AudioInterface::AudioInterfaceManager& GetAudioInterface() const;
   CPU::CPUManager& GetCPU() const;
   CoreTiming::CoreTimingManager& GetCoreTiming() const;