file_sys: Implement function to apply IPS patches

src/core/file_sys/ips_layer.h

@@ -0,0 +1,15 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+
+#include "core/file_sys/vfs.h"
+
+namespace FileSys {
+
+VirtualFile PatchIPS(const VirtualFile& in, const VirtualFile& ips);
+
+} // namespace FileSys