cpufreq: Add cpu utilization statistics to aid decisions made by userspace.

Understanding system load as seen by cpufreq can help userspace
algorithms make better decisions to improve system responsiveness.
One such example would be the MP decision algorithm which mines
various system info to make decisions on hotplugging in/out
the additional cores.

Change-Id: I277db7e1a7803a3822b61e7befa25131487cfe17
Signed-off-by: Anitha Anand <anithas@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
[zwliew: use userspace max freq instead to account for overclocking]
Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>
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>
[zwliew: only take the cpufreq driver specific parts]
Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>
cpufreq: interactive: update CPU utilisation

To be used in u8500_hotplug

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>
cpufreq: Initial CPU utilization should be 0

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