CPUCoreBase: Make the GetName() member function const qualified

This function should have no need to modify internal class state.

Source/Core/Core/FifoPlayer/FifoPlayer.cpp

@@ -102,7 +102,7 @@ public:
     PanicAlertT("Cannot SingleStep the FIFO. Use Frame Advance instead.");
   }
 
-  const char* GetName() override { return "FifoPlayer"; }
+  const char* GetName() const override { return "FifoPlayer"; }
   void Run() override
   {
     while (CPU::GetState() == CPU::State::Running)