Create headers for Game States (#2482)

* make headers for gamestates

* fixes

* fixes 2

* bss

include/setup_state.h

@@ -0,0 +1,13 @@
+#ifndef SETUP_STATE_H
+#define SETUP_STATE_H
+
+#include "z64game.h"
+
+typedef struct SetupState {
+    /* 0x00 */ GameState state;
+} SetupState; // size = 0xA4
+
+void Setup_Init(GameState* thisx);
+void Setup_Destroy(GameState* thisx);
+
+#endif