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.

CRs-fixed: 344675
Signed-off-by: Anitha Anand <anithas@codeaurora.org>
(cherry picked from commit cbeef6aafc4964c4a6cfafd26b23eaccd40804b4)

Change-Id: I7b4450ed7b3bf8196870717e1907fd93c5cfbe98
Signed-off-by: Ramakrishna Prasad N <crpn@codeaurora.org>