msm: hotplug: Optimize latencies

Before this patch it took the algorithm too long to
react on sudden load spikes, although only noticable
in benchmarks. We would cycle 5-6 times until the
buffer average was finally high enough to trigger a
new target.  Improve latencies by instantly onlining
all cpus if current load on any cpu is above a certain
threshold.

fast_lane_load should not be higher than 78 as load
per cpu won't be above this value in our metric.

First cycle in hackbench
Before: 1.253sec
After: 0.796sec