ASoc: Add Texas Instruments TAS2562 amplifier binding

Add the DT binding for the TAS2562 amplifier.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Link: https://lore.kernel.org/r/20191008181517.5332-1-dmurphy@ti.com


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