* amadeus: adjust VirtualDevice channel configuration reporting with HardwareDevice
* audio: sdl2: Do not report 5.1 if device doesn't support it
SDL2 5.1 to Stereo conversion is terrible and make everything sound
quiet.
Let's not expose 5.1 if not truly supported by the device.
* 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* Remove outdated comment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
