Merge "libeffects: Add multichannel support to Reverb" am: ba88b6bfd1 am: 6a715cf983 am: a364a910cf am: 291cd2df2c am: 181438e955

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/1396509

Change-Id: Iad15751dd5c964ade61ead92ab8369cb0302dca4