Fix layering of MachineValueType.h by moving it from CodeGen to Support

This is used by llvm tblgen as well as by LLVM Targets, so the only
common place is Support for now. (maybe we need another target for these
sorts of things - but for now I'm at least making them correct & we can
make them better if/when people have strong feelings)

llvm-svn: 328395
diff --git a/llvm/utils/TableGen/CodeGenInstruction.h b/llvm/utils/TableGen/CodeGenInstruction.h
index 9cff95b..9e76a5b 100644
--- a/llvm/utils/TableGen/CodeGenInstruction.h
+++ b/llvm/utils/TableGen/CodeGenInstruction.h
@@ -15,7 +15,7 @@
 #define LLVM_UTILS_TABLEGEN_CODEGENINSTRUCTION_H
 
 #include "llvm/ADT/StringRef.h"
-#include "llvm/CodeGen/MachineValueType.h"
+#include "llvm/Support/MachineValueType.h"
 #include "llvm/Support/SMLoc.h"
 #include <string>
 #include <utility>