arm64: dts: qcom: sm8450: Add RPMh stats

SM8450 also exposes RPMh stats, hook them up for low power state
monitoring.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230811-topic-8450_stats-v1-1-f26ae3fdf2cf@linaro.org


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