hidl2aidl: cpp backend note delete translate

If you disable this, there will also be build errors that need to be
fixed.

Bug: N/A
Test: N/A
Change-Id: I00b602fd914e42fed3516d89d7648cd4bad9ce38
diff --git a/hidl2aidl/main.cpp b/hidl2aidl/main.cpp
index 9a3b50e..bc67b28 100644
--- a/hidl2aidl/main.cpp
+++ b/hidl2aidl/main.cpp
@@ -226,6 +226,8 @@
     out << "        cpp: {\n";
     out << "            // FIXME should this be disabled?\n";
     out << "            // prefer NDK backend which can be used anywhere\n";
+    out << "            // If you disable this, you also need to delete the C++\n";
+    out << "            // translate code.\n";
     out << "            enabled: true,\n";
     out << "        },\n";
     out << "        java: {\n";