Compensate for the LevelController gain in the IntelligibilityEnhancer

R=peah@webrtc.org

Review URL: https://codereview.webrtc.org/2112553003 .

Cr-Original-Commit-Position: refs/heads/master@{#13353}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 5041110b94c85ac177f37cd46c65547182615b37
4 files changed