arm64: dts: qcom: msm8998: Add PSCI cpuidle low power states

Add device bindings for cpuidle states for cpu devices.

[marc: rebase, fix arm,psci-suspend-param, fix entry-latency-us]
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Marc Gonzalez <marc.w.gonzalez@free.fr>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>