Move MMX class to the implementation side.

Bug swiftshader:10

Change-Id: I24fc66248bd2f66d2e8bc2b2a15e6c8fadc47efb
Reviewed-on: https://swiftshader-review.googlesource.com/7213
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
diff --git a/src/Reactor/Nucleus.cpp b/src/Reactor/Nucleus.cpp
index 0a648bd..1311488 100644
--- a/src/Reactor/Nucleus.cpp
+++ b/src/Reactor/Nucleus.cpp
@@ -846,6 +846,12 @@
 		return Nucleus::createGEP(address, index);
 	}
 
+	class MMX : public Variable<MMX>
+	{
+	public:
+		static Type *getType();
+	};
+
 	Type *MMX::getType()
 	{
 		return Type::getX86_MMXTy(*Nucleus::getContext());