[CMake] libclang: Update GENERATED_HEADERS with actually used.

+  ClangAttrVisitor
+  ClangCommentCommandList

llvm-svn: 199999
GitOrigin-RevId: 518490b94981c522f81255945f31c1e020991054
diff --git a/tools/libclang/CMakeLists.txt b/tools/libclang/CMakeLists.txt
index 2dd4dbf..97203b0 100644
--- a/tools/libclang/CMakeLists.txt
+++ b/tools/libclang/CMakeLists.txt
@@ -56,6 +56,8 @@
   ClangAttrClasses
   ClangAttrList
   ClangAttrParsedAttrList
+  ClangAttrVisitor
+  ClangCommentCommandList
   ClangCommentNodes
   ClangDiagnosticCommon
   ClangDiagnosticFrontend