[MIPS] Add support to gyp files to build Native Client inside of Chromium

src/trusted/validator/x86/ncval_reg_sfi/ncval_reg_sfi.gyp

 # Copyright (c) 2011 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # TODO(bradchen): eliminate need for the warning flag removals below
 {
   'includes': [
     '../../../../../build/common.gypi',
   ],
   'target_defaults': {
@@ skipping 118 matching lines @@
             'ncval_reg_sfi_x86_64',
            ],
           'variables': {
             'target_base': 'ncval_reg_sfi_verbose',
           },
         }],
     }],
     [ 'target_arch=="arm"', {
       'targets': []
     }],
+    [ 'target_arch=="mipsel"', {
+      'targets': []
+    }],
   ],
 }