msm: mpdecision: make runqueue divisor configurable via sysfs

The runqueue divisor controls how sensitive mpdecision is to
changes in runqueue depth - if the runqueue divisor is increased,
updates to TZ are made less frequently. It is desirable to be able
to easily change this parameter from userspace.

(cherry picked from commit f5d5d54a8c64337115a44d9d9292c677042c9fc1)

Change-Id: Ibfadc7fba413ae08467ded737e192fd918e97755
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>