Remove "multichannel" from parameter to match interface name.
Remove "multichannel" from parameter to match interface name.

TBR=mgraczyk@google.com

Review URL: https://codereview.webrtc.org/1250423004

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#9635}

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