MB: Remove unnecessary configs.
MB: Remove unnecessary configs.

https://codereview.chromium.org/1808093002/ was rolled in
a while ago, so we can now clean these up.

NOTRY=True

Review URL: https://codereview.webrtc.org/1847533002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#12172}

ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc