arm64: dts: sdm845: Add dynamic CPU power coefficients

Add dynamic power coefficients for the Silver and Gold CPU cores of
the Qualcomm SDM845.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>