Change mbedtls_ssl_parse_server_name_ext base on comments

Change-Id: I4ae831925cb1899afafb7dc626bfad9be24a5c8c
Signed-off-by: XiaokangQian <xiaokang.qian@arm.com>
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index e48a8ca..854ec63 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -1409,8 +1409,8 @@
 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
             case MBEDTLS_TLS_EXT_SERVERNAME:
                 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ServerName extension" ) );
-                ret = mbedtls_ssl_parse_servername_ext( ssl, ext + 4,
-                                                        ext + 4 + ext_size );
+                ret = mbedtls_ssl_parse_server_name_ext( ssl, ext + 4,
+                                                         ext + 4 + ext_size );
                 if( ret != 0 )
                     return( ret );
                 break;