ASoC: tas2770: Convert tas2770 binding to yaml

Convert the tas2770 binding to yaml format.
Add in the reset-gpio to the binding as it is in the code but not
documented in the binding.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200720181202.31000-1-dmurphy@ti.com


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