Fixed doxygen blocks
(cherry picked from commit 77db6ce3481ad610ee786d5ab171d5d10c1cb59d)
diff --git a/include/polarssl/des.h b/include/polarssl/des.h
index 653e68b..a6be471 100644
--- a/include/polarssl/des.h
+++ b/include/polarssl/des.h
@@ -213,7 +213,7 @@
                      const unsigned char *input,
                      unsigned char *output );
 
-/*
+/**
  * \brief          Checkup routine
  *
  * \return         0 if successful, or 1 if the test failed