TLS1.3: Add client finish processing in client side

Signed-off-by: XiaokangQian <xiaokang.qian@arm.com>
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 6deab2a..a0f0c9c 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -1618,11 +1618,9 @@
 /*
  * Handler for MBEDTLS_SSL_CLIENT_FINISHED
  */
-static int ssl_tls1_3_write_client_finished( mbedtls_ssl_context *ssl )
+static int ssl_tls13_write_client_finished( mbedtls_ssl_context *ssl )
 {
-    MBEDTLS_SSL_DEBUG_MSG( 1, ( "%s hasn't been implemented", __func__ ) );
-    mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_FLUSH_BUFFERS );
-    return( 0 );
+    return ( mbedtls_ssl_tls1_3_finished_out_process( ssl ) );
 }
 
 /*
@@ -1689,7 +1687,7 @@
             break;
 
         case MBEDTLS_SSL_CLIENT_FINISHED:
-            ret = ssl_tls1_3_write_client_finished( ssl );
+            ret = ssl_tls13_write_client_finished( ssl );
             break;
 
         case MBEDTLS_SSL_FLUSH_BUFFERS: