fgo: fgohook finally added

Credits:
- Coburn
- domeori
- Mitsuhide
- OLEG
- rakisaionji

fgohook/io4.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <windows.h>
+
+#include "board/io4.h"
+
+HRESULT fgo_io4_hook_init(const struct io4_config *cfg);