dt-bindings: power: rpmpd: Add SC8180X to rpmpd binding

Add compatible and constants for the power domains exposed by the RPMH
in the Qualcomm SC8180X platform.

Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210120225037.1611353-1-bjorn.andersson@linaro.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>