[OPENMP] Add reverse_offload clause to requires directive

llvm-svn: 343711
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 08cfa6b..81ef885 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -6935,3 +6935,5 @@
 
 void OMPClauseWriter::VisitOMPUnifiedSharedMemoryClause(
     OMPUnifiedSharedMemoryClause *) {}
+
+void OMPClauseWriter::VisitOMPReverseOffloadClause(OMPReverseOffloadClause *) {}