Remove rtc_enable_android_opensl.
Remove rtc_enable_android_opensl.

This GN argument is unused.

Bug: webrtc:10198
Change-Id: I470e3725758fc7d6e80673842fd36fa2f22339a3
Reviewed-on: https://webrtc-review.googlesource.com/c/116993
Reviewed-by: Henrik Andreassson <e468f06af92d21183a2a635f545ff5cefc8c8b65@webrtc.org>
Commit-Queue: Mirko Bonadei <d2c43c210eae6feef04f53bae50885e8152edcca@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#26232}
TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc