MIPS: Match max property descriptor length to corresponding bit fields.

Port r17823 (b1b8ae0)

BUG=v8:3010
LOG=N
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/62833011

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17851 ce2b1a6d-e550-0410-aec6-3dcde31c8c00