[presubmit] Enable readability/namespace linter checking.

src/ppc/macro-assembler-ppc.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PPC_MACRO_ASSEMBLER_PPC_H_
 #define V8_PPC_MACRO_ASSEMBLER_PPC_H_
 
 #include "src/assembler.h"
 #include "src/bailout-reason.h"
 #include "src/frames.h"
@@ skipping 1548 matching lines @@
 #ifdef GENERATED_CODE_COVERAGE
 #define CODE_COVERAGE_STRINGIFY(x) #x
 #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm)    \
   masm->stop(__FILE_LINE__); \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
-}
-}  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_PPC_MACRO_ASSEMBLER_PPC_H_