Core/IOS/IOS: Remove global system accessor from Init()

Removes the final global system accessor from the main IOS code by
passing the system instance through it.

Source/Core/Core/HW/HW.cpp

@@ -57,7 +57,7 @@ void Init(Core::System& system, const Sram* override_sram)
   if (SConfig::GetInstance().bWii)
   {
     IOS::Init();
-    IOS::HLE::Init();  // Depends on Memory
+    IOS::HLE::Init(system);  // Depends on Memory
   }
 }
 

Source/Core/Core/IOS/DI/DI.h

@@ -120,7 +120,7 @@ private:
   };
 
   friend class ::CBoot;
-  friend void ::IOS::HLE::Init();
+  friend void ::IOS::HLE::Init(Core::System&);
 
   void ProcessQueuedIOCtl();
   std::optional<DIResult> StartIOCtl(const IOCtlRequest& request);

Source/Core/Core/IOS/IOS.cpp

@@ -949,9 +949,8 @@ static void FinishPPCBootstrap(Core::System& system, u64 userdata, s64 cycles_la
   INFO_LOG_FMT(IOS, "Bootstrapping done.");
 }
 
-void Init()
+void Init(Core::System& system)
 {
-  auto& system = Core::System::GetInstance();
   auto& core_timing = system.GetCoreTiming();
 
   s_event_enqueue =

Source/Core/Core/IOS/IOS.h

@@ -216,7 +216,7 @@ private:
 };
 
 // Used for controlling and accessing an IOS instance that is tied to emulation.
-void Init();
+void Init(Core::System& system);
 void Shutdown();
 EmulationKernel* GetIOS();