MIPS: Fix clang compilation error.

Port r24662 (4722032)

BUG=
R=dusan.milosavljevic@imgtec.com

Review URL: https://codereview.chromium.org/657413003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24669 ce2b1a6d-e550-0410-aec6-3dcde31c8c00