Move gn goma setup to gcc_toolchain

build/toolchain/fnl/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/toolchain/gcc_toolchain.gni")
 
 declare_args() {
   toolchain_prefix = ""
 }
 
 gcc_toolchain("target") {
   assert(toolchain_prefix != "", "Must provide toolchain_prefix")
 
   cc = "${toolchain_prefix}gcc"
   cxx = "${toolchain_prefix}g++"
   ar = "${toolchain_prefix}ar"
   ld = cxx
   readelf = "${toolchain_prefix}readelf"
   nm = "${toolchain_prefix}nm"
 
   toolchain_cpu = "${target_cpu}"
   toolchain_os = "linux"
   is_clang = is_clang
+  use_ccache = false
+  use_goma = false
+
 }