MIPS: build fix for r19380

Port r19381 (5476e11b)

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/163953014

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19395 ce2b1a6d-e550-0410-aec6-3dcde31c8c00