fixup! Add SM4 block cipher

Fix the initial comment in src/ciphers/sm4.c

Author: levitte

src/ciphers/sm4.c

@@ -1,25 +1,19 @@
-/* LibTomCrypt, modular cryptographic library -- Tom St Denis
- *
- * LibTomCrypt is a library that provides various cryptographic
- * algorithms in a highly modular and flexible manner.
- *
- * The library is free for all purposes without any express
- * guarantee it works.
- */
-
-/*
- * @brief       SM4 block cipher algorithm
- * @date        Oct 2018
- * @author      Chao Wei
- *
- * SM4 (formerly SMS4) is a block cipher used in the Chinese National
- * Standard for Wireless LAN WAPI (Wired Authentication and Privacy
- * Infrastructure).
- * --from wikipedia:
- *  https://en.wikipedia.org/wiki/SM4_(cipher)
- *
- * This implimentation follows Chinese National Standard
- *      GM/T 0002-2012
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+/**
+   @brief       SM4 block cipher algorithm
+   @date        Oct 2018
+   @author      Chao Wei
+
+   SM4 (formerly SMS4) is a block cipher used in the Chinese National
+   Standard for Wireless LAN WAPI (Wired Authentication and Privacy
+   Infrastructure).
+   --from wikipedia:
+    https://en.wikipedia.org/wiki/SM4_(cipher)
+
+   This implimentation follows Chinese National Standard
+        GM/T 0002-2012
  */
 #include "tomcrypt_private.h"
 
@@ -493,4 +487,3 @@ const struct ltc_cipher_descriptor sm4_desc = {
 /* ref:         $Format:%D$ */
 /* git commit:  $Format:%H$ */
 /* commit time: $Format:%ai$ */
-