remove variable initial

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index cdffd97..511ba1f 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -1147,8 +1147,7 @@
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char *buf;
-    size_t buf_len = 0;
-    size_t msg_len = 0;
+    size_t buf_len, msg_len;
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write encrypted extensions" ) );