ASoC: dt-bindings: Add a new compatible for the A64 codec

The audio codecs in the A33 and A64 are both integrated variants of the
X-Powers AC100 codec. However, there are some differences between them
that merit having a separate compatible:
 - The A64 has a second DRC block, not present in the AC100 or A33.
 - The A33 has some extra muxing options for AIF1/2/3 in the
   AIF3_SGP_CTRL register, which are not present in the AC100 or A64.
 - The A33 is missing registers providing jack detection functionality.
 - The A33 is claimed to invert LRCK, but this is not seen on A64.

Since the driver will continue to work on the A64 using the A33
compatible, albeit without jack detection functionality and with
possibly inverted channels, as it does now, allow the A33 compatible
to be used as a fallback.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200726012557.38282-2-samuel@sholland.org
Signed-off-by: Mark Brown <broonie@kernel.org>