[OpenCL] Move OpenCLImageTypes.def from clangAST to clangBasic library.

Putting OpenCLImageTypes.def to clangAST library violates layering requirement: "It's not OK for a Basic/ header to include an AST/ header".
This fixes the modules build.

Differential revision: http://reviews.llvm.org/D18954
Reviewers: Richard Smith, Vassil Vassilev.

llvm-svn: 266180
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 152f46a..b38aeff 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -6303,7 +6303,7 @@
     case BuiltinType::ObjCSel:
 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
     case BuiltinType::Id:
-#include "clang/AST/OpenCLImageTypes.def"
+#include "clang/Basic/OpenCLImageTypes.def"
     case BuiltinType::OCLSampler:
     case BuiltinType::OCLEvent:
     case BuiltinType::OCLClkEvent: