Enable 4-channel input

This requires adding channel remap functionality to input/output streams.
Number of channels provided by hardware might be different from what framework expects.
For example in case of Pixel C there is I2S bus to rt5677 codec shared by both capture and
playback. If we want to record 4-channel input from mics and playback stereo at the same time
then HW format has to be 4-channel (I2S cannot have different formats for capture/playback).

In such case we need to adjust number of audio channels.

Change-Id: I6917423379999bb98841db9e42373136c747a82a
2 files changed