ASoC: dt-bindings: pcm3168a: Update the optional RST gpio for clarity

Use the standard name for the gpion in DT: reset-gpios

Document that the RST line is low active and update the example
accordingly.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20191120131753.6831-2-peter.ujfalusi@ti.com


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