Move libultra variables to their respective headers (#1369)

* internal_rsp; move size_t and NULL to ultratypes.h

* guint.h

* Move system variables to os_system.h

* controller, pi and vi

* osint.h

* piint.h

* siint, ucode, viint, voiceinternal

* Remove remaining variables from variables.h

* format

* final renames

* bss

* review

* review

src/code/z_parameter.c

@@ -1,4 +1,5 @@
 #include "global.h"
+#include "PR/gs2dex.h"
 #include "sys_cfb.h"
 #include "z64snap.h"
 #include "z64view.h"