[CodeGen] Fix included headers.

Remove the included Parse header because CodeGen should not depend on Parse.
Instead, include the Lex headers that it needs instead.

llvm-svn: 347727
diff --git a/clang/lib/CodeGen/MacroPPCallbacks.cpp b/clang/lib/CodeGen/MacroPPCallbacks.cpp
index 05acc9b..013ca15 100644
--- a/clang/lib/CodeGen/MacroPPCallbacks.cpp
+++ b/clang/lib/CodeGen/MacroPPCallbacks.cpp
@@ -14,7 +14,8 @@
 #include "MacroPPCallbacks.h"
 #include "CGDebugInfo.h"
 #include "clang/CodeGen/ModuleBuilder.h"
-#include "clang/Parse/Parser.h"
+#include "clang/Lex/MacroInfo.h"
+#include "clang/Lex/Preprocessor.h"
 
 using namespace clang;