ASoC: qcom: sc8280xp: Limit speaker digital volumes

ASoC: qcom: sc8280xp: Limit speaker digital volumes

Limit the speaker digital gains to 0dB so that the users will not damage them.
Currently there is a limit in UCM, but this does not stop the user form
changing the digital gains from command line. So limit this in driver
which makes the speakers more safer without active speaker protection in
place.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20231204124736.132185-3-srinivas.kandagatla@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>