cpufreq: qcom-hw: Use devm_platform_ioremap_resource() to simplify code

devm_platform_ioremap_resource() is the combination of
platform_get_resource() and devm_ioremap_resource(). Hence, use it to
simplify the code a bit.

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>