src: drop 'virtual' from functions marked 'final' or 'override'

Change-Id: Ieb6df864ab82f77b2bee9e83aa0bfa2005715950
Refs: #3857
diff --git a/src/security/transform/stream-sink.hpp b/src/security/transform/stream-sink.hpp
index ed41cbd..f384dc4 100644
--- a/src/security/transform/stream-sink.hpp
+++ b/src/security/transform/stream-sink.hpp
@@ -47,13 +47,13 @@
    *
    * @return number of bytes that have been written into the stream
    */
-  virtual size_t
+  size_t
   doWrite(const uint8_t* buf, size_t size) final;
 
   /**
    * @brief Finalize sink processing
    */
-  virtual void
+  void
   doEnd() final;
 
 private: