ASoC: es8316: fix inverted L/R of headphone mixer volume

This patch fixes inverted Left-Right channel of headphone mixer
volume by wrong shift_left, shift_right values.

Signed-off-by: Katsuhiro Suzuki <katsuhiro@katsuster.net>
Reviewed-by: Daniel Drake <drake@endlessm.com>
Link: https://lore.kernel.org/r/20190826153900.25969-2-katsuhiro@katsuster.net


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