ASoc: nau8810: add AUX related dapm widgets and routes

This patch implements the following features:
- AUX input for recording.
- An input AUX output to SPK/MOUT.

Signed-off-by: Seven Lee <wtli@nuvoton.com>
Link: https://lore.kernel.org/r/20200429090002.28556-1-wtli@nuvoton.com


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