arm64: dts: qcom: sc7280: Add power-domains for cpuidle states

Add power-domains for cpuidle states to use psci os-initiated idle states.

Cc: devicetree@vger.kernel.org
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Link: https://lore.kernel.org/r/20230703085555.30285-4-quic_mkshah@quicinc.com
[bjorn: Corrected psci child node names to match binding]
Signed-off-by: Bjorn Andersson <andersson@kernel.org>