cpufreq: qcom-hw: Use cached dev pointer in probe()

There are multiple instances of dev pointer used in the probe() function.
Instead of referencing pdev->dev all the time, let's use a cached dev
pointer to simplify the code.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>