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.

Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
Change-Id: Ia573748dadd7f5eb9cc2686c99fef40b8acbdae2