ASoC: dt-bindings: Add dt binding for lpass hdmi

Adds bindings for lpass hdmi interface
which can support audio path over dp.

Signed-off-by: V Sujith Kumar Reddy <vsujithk@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Srinivasa Rao <srivasam@codeaurora.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/1602134223-2562-3-git-send-email-srivasam@codeaurora.org


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