MIPS: Ensure that soft-deopts don't count against opt_count

Port r14658 (12c49bd)

This makes sure that Crankshaft doesn't disable optimization to early on hot functions that still contain unexecuted code without type information.

BUG=

Review URL: https://codereview.chromium.org/15005008
Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14672 ce2b1a6d-e550-0410-aec6-3dcde31c8c00