libretro: Fix display rendering in D3D11/OpenGL

src/duckstation-libretro/libretro_d3d11_host_display.h

@@ -12,7 +12,6 @@ public:
   static bool RequestHardwareRendererContext(retro_hw_render_callback* cb);
 
   bool CreateRenderDevice(const WindowInfo& wi, std::string_view adapter_name, bool debug_device) override;
-  void DestroyRenderDevice();
 
   void ResizeRenderWindow(s32 new_window_width, s32 new_window_height) override;
 
@@ -20,6 +19,9 @@ public:
 
   bool Render() override;
 
+protected:
+  void DestroyResources() override;
+
 private:
   bool CheckFramebufferSize(u32 width, u32 height);