pegasusq: Replace governor nr_running logic

Remove pegasusq's own nr_running() averaging logic and replace it with
Nvidia's avg_nr_running() in-scheduler collecting mechanism.

Compared to the old logic, the new one is able to do absolutely exact
runqueue monitoring as it is averaging deep inside the scheduler, whilst
the old logic could only do snap-shots every 10ms.

Furthermore, we're able to decrease runqueue peaks and lows by the
sliding-window averaging done by avg_nr_running(), averaging runqueues
over 134ms and retaining the precision.

We also remove a whole separate workqueue from the kernel and a lot of
overhead and code from inside the governor.

Conflicts:

	drivers/cpufreq/cpufreq_pegasusq.c