fix name conversion issue for tls13 server entry

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 a567277..0dcd7ed 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -25,7 +25,7 @@
 
 #include "ssl_misc.h"
 
-int mbedtls_ssl_handshake_server_step_tls1_3( mbedtls_ssl_context *ssl )
+int mbedtls_ssl_tls13_handshake_server_step( mbedtls_ssl_context *ssl )
 {
     ((void) ssl);
     return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );