Pica: Create 'State' structure and move state memory there.

src/video_core/pica.cpp

@@ -0,0 +1,20 @@
+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <string.h>
+
+#include "pica.h"
+
+namespace Pica {
+
+State g_state;
+
+void Init() {
+}
+
+void Shutdown() {
+    memset(&g_state, 0, sizeof(State));
+}
+
+}