Revert "Don't show HIDL_GENERATED_ with -Lc++-impl."

This reverts commit 21247bffb412ede7d5a752afa489d1567cacad99.

Change-Id: I2509c696001f166dc40762d59e74c46265d16b5c
diff --git a/generateCppImpl.cpp b/generateCppImpl.cpp
index caa0ac0..25310f5 100644
--- a/generateCppImpl.cpp
+++ b/generateCppImpl.cpp
@@ -104,7 +104,7 @@
 
     Formatter out(file);
 
-    const std::string guard = makeHeaderGuard(baseName, false /* indicateGenerated */);
+    const std::string guard = makeHeaderGuard(baseName);
 
     out << "#ifndef " << guard << "\n";
     out << "#define " << guard << "\n\n";