Conv from UTF-8 to ASCII

`file *.c` to see file types (ASCII or UTF-8), convert UTF-8 (with BOM) to ASCII

```sh
sed '1s/^\xEF\xBB\xBF//'  sm4.c | iconv -f UTF-8 -t ASCII//TRANSLIT > temp.c
mv temp.c sm4.c
```

include/gmssl/oid.h

@@ -147,7 +147,7 @@ enum {
 	OID_aes192_cbc,
 	OID_aes256_cbc,
 
-	OID_aes128, // 没有OID
+	OID_aes128, // No OID
 
 	OID_ecdsa_with_sha1,
 	OID_ecdsa_with_sha224,