ASoC: rt5682: Fix the vol+ button detection issue

Fix the wrong button vol+ detection issue with some brand headsets
by fine tuning the threshold of button vol+ and SAR ADC button accuracy.

Signed-off-by: Derek Fang <derek.fang@realtek.com>
Link: https://lore.kernel.org/r/20210825040346.28346-1-derek.fang@realtek.com


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