ASoC: Document Tegra234 APE support

Update binding docs for devices which are part of APE subsystem
on Tegra234 chip.

Signed-off-by: Sameer Pujar <spujar@nvidia.com>
Link: https://lore.kernel.org/r/1643373476-8538-4-git-send-email-spujar@nvidia.com
Signed-off-by: Mark Brown <broonie@kernel.org>