ASoC: qcom: audioreach: Add 4 channel support

Add support four channel streams.  Map channel 3 and 4 to left/right
surround ("quad(side)" from ffmpeg standard channel list) to match what
is in qdsp6/q6dsp-common.c driver.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://msgid.link/r/20231130180758.212172-3-krzysztof.kozlowski@linaro.org


Signed-off-by: Mark Brown <broonie@kernel.org>