ASoC: meson: g12a: add internal DAC glue driver

Add support for the internal audio DAC glue found on the Amlogic g12a
and sm1 SoC families. This allows to connect the TDM outputs of the SoC
to the internal t9015 audio DAC.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20200221153607.1585499-3-jbrunet@baylibre.com


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