msm: rq_stats: Support to know cpu utilization in userspace

Support to read utilization stats from userspace, used by
mpdecision. This implementation is independent of governor
and sampling rates.

Change-Id: I678c7462ba77d84ce4c51c36a61da7ac99ffecc8
Signed-off-by: Narayanan Gopalakrishnan <nargop@codeaurora.org>