cpufreq: Create a helper function to get CPU utilization

Use the new cpufreq_quick_get_util function in dyn_hotplug driver

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>

adapted to this kernel for hotplug driver

Change-Id: I1ca2443e50744b15067de7c869fddd75c52d9794
cpufreq: Initial CPU utilization should be 0

Change-Id: I0400fc9b9a9b53ccc836107cba263dbc665ed3f3
Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>