tls13: Rename ssl_tls13_write_hello_retry_request_coordinate

Rename ssl_tls13_write_hello_retry_request_coordinate to
ssl_tls13_prepare_hello_retry_request as it is more
aligned with what the function does.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 0b23b58..bfb2204 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -1307,8 +1307,7 @@
 /*
  * Handler for MBEDTLS_SSL_HELLO_RETRY_REQUEST
  */
-static int ssl_tls13_write_hello_retry_request_coordinate(
-                                                    mbedtls_ssl_context *ssl )
+static int ssl_tls13_prepare_hello_retry_request( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     if( ssl->handshake->hello_retry_request_count > 0 )
@@ -1342,7 +1341,7 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello retry request" ) );
 
-    MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_hello_retry_request_coordinate( ssl ) );
+    MBEDTLS_SSL_PROC_CHK( ssl_tls13_prepare_hello_retry_request( ssl ) );
 
     MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg(
                               ssl, MBEDTLS_SSL_HS_SERVER_HELLO,