INTERNAL: arm64: dts: qcom: enable voltage scaling (opp)

Provide the regulator that will control the cpu supplies and the
voltage ranges for each valid frequency.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
(cherry picked from commit 0a78b6ee875dfe0fa4ed0087380445101d04d51b
https://github.com/ldts/qualcomm-lt-kernel

)
Signed-off-by: Khasim Syed Mohammed <khasim.mohammed@linaro.org>