ASoC: rt5682: Adjust headset volume button threshold again

This reverts commit 6d20bf7c.
Since it may risk affecting other headset Vol- button.

Signed-off-by: Derek Fang <derek.fang@realtek.com>
Link: https://lore.kernel.org/r/20210811083750.26680-1-derek.fang@realtek.com


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