ASoC: rt5677: Allow VAD to be shut on/off at all times

ASoC: rt5677: Allow VAD to be shut on/off at all times

Due to limitations of the clocking configuration, we have no way of
scheduling our hibernation before the bdw dsp hibernates. This causes
issues when the system suspends with an open stream. We need userspace
to toggle the kcontrol before we are suspended so that any writes on
suspend are not lost and we don't corrupt the regmap.

Signed-off-by: Curtis Malainey <cujomalainey@chromium.org>
Link: https://lore.kernel.org/r/20191106011335.223061-9-cujomalainey@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>