ASoC: Add sc7180 lpass cpu node

Add dt-bindings to support "qcom,lpass-cpu-sc7180" node.

Signed-off-by: Rohit kumar <rohitkr@codeaurora.org>
Link: https://lore.kernel.org/r/1597402388-14112-8-git-send-email-rohitkr@codeaurora.org
Signed-off-by: Mark Brown <broonie@kernel.org>