arm64: dts: qcom: qcs404: Add DVFS support

arm64: dts: qcom: qcs404: Add DVFS support

Support dynamic voltage and frequency scaling on qcs404.

CPUFreq will soon be superseded by Core Power Reduction (CPR, a form
of Adaptive Voltage Scaling found on some Qualcomm SoCs like the
qcs404).

Due to the CPR upstreaming already being in progress - and some
commits already merged -  the following commit will need to be
reverted to enable CPUFreq support

   Author: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
   Date:   Thu Jul 25 12:41:36 2019 +0200
       cpufreq: Add qcs404 to cpufreq-dt-platdev blacklist

Co-developed-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20191125142511.681149-5-niklas.cassel@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>