cpufreq: qcom-hw: Add cpufreq support for SM8250 SoC

SM8250 SoC uses EPSS block for carrying out the cpufreq duties. Hence, add
support for it in the driver with relevant dev data.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Amit Kucheria <amitk@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>