cpufreq: qcom-hw: Register an Energy Model

Try and register an Energy Model from qcom-cpufreq-hw to allow
interested sub-systems like the task scheduler to use the provided
information.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
[ Viresh: Rebased over cpufreq related changes ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>