Document additional compatibles that can be used similarly to qcom,rpm-stats
for older RPM firmware versions that have the sleep stats at a fixed offset
rather than a dynamic one. The exact offset might vary depending on the SoC
so use SoC-specific compatible names to avoid confusion.

Cc: Maulik Shah <mkshah@codeaurora.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211119213953.31970-2-stephan@gerhold.net