Turn down optimization in cutils for caf variants

Summary:
We don't know why yet, but heavy optimization has been breaking
CAF media in numerous places, including wilhelm.

Test Plan: confirmed on m7, should be g2g

Reviewers: synergy, anders3408, jriordan001, raymanfx, donald.munn, rlasalle15

Differential Revision: http://review.codefirex.com/D378