fix coding style issue

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index cd929ce..8996e8a 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -107,7 +107,7 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write client hello" ) );
     /* client_hello_process haven't finished */
-    ret=MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
+    ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
     return ret;
 }