* amadeus: Allow 5.1 sink output
Also add a simple Stereo to 5.1 change for device sink.
Tested against NES - Nintendo Switch Online that output stereo on the
audio renderer.
* Remove outdated comment
* amadeus: Fix wrong channel mapping check
This was always going to happens, as a result quadratic would break and
move index after the channel count point, effectively breaking
input/output indices.
* amadeus: Fix reverb 3d early delay wrong output index
