[dfsan] Revert dfsan_set_label removal

It's part of interface, maybe it is used in external code.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@371691 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/sanitizer/dfsan_interface.h b/include/sanitizer/dfsan_interface.h
index 7960d9e..81546e5 100644
--- a/include/sanitizer/dfsan_interface.h
+++ b/include/sanitizer/dfsan_interface.h
@@ -111,6 +111,11 @@
 #ifdef __cplusplus
 }  // extern "C"
 
+template <typename T>
+void dfsan_set_label(dfsan_label label, T &data) { // NOLINT
+  dfsan_set_label(label, (void *)&data, sizeof(T));
+}
+
 #endif
 
 #endif  // DFSAN_INTERFACE_H