illumos gate

apix_redistribute_compute() runs periodically, computing a bunch of stats as to busy interrupts on CPUs.
It then does nothing with that information.

It's clearly a copy and paste from pcplusmp's apic_redistribute_compute(), which supposedly does do
something, but only when some variable is set, and that defaults to 0.

On top of all this, we have intrd apparently doing the same job.

I think all of this should be ripped out.