- Changed text for return 0 lines

diff --git a/include/polarssl/camellia.h b/include/polarssl/camellia.h
index e9ded15..ed05990 100644
--- a/include/polarssl/camellia.h
+++ b/include/polarssl/camellia.h
@@ -78,7 +78,7 @@
  * \param input    16-byte input block
  * \param output   16-byte output block
  * 
- * \return         0
+ * \return         0 if successful
  */
 int camellia_crypt_ecb( camellia_context *ctx,
                     int mode,