Fix documentation issues found by Clang
diff --git a/include/polarssl/pkcs5.h b/include/polarssl/pkcs5.h
index b8c742e..f83c8cd 100644
--- a/include/polarssl/pkcs5.h
+++ b/include/polarssl/pkcs5.h
@@ -77,7 +77,7 @@
  * \param pbe_params the ASN.1 algorithm parameters
  * \param mode       either PKCS5_DECRYPT or PKCS5_ENCRYPT
  * \param pwd        password to use when generating key
- * \param plen       length of password
+ * \param pwdlen     length of password
  * \param data       data to process
  * \param datalen    length of data
  * \param output     output buffer