qcom-cpufreq: Implement resolve_freq method

The resolve_freq method is needed for schedutil to avoid
calling into cpufreq for changing to the same frequency
again and again.

Change-Id: Ia03cc49e3b8bad68fa2fda5688c64233b4b2c48d
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>