Add in a very, very hacked up version of pmcstat.c from usr.sbin/pmcstat in freebsd.

This is part refactor, part hack to get this thing into shape to spit out _something_.

It's temporary - I'll eventually replace it with something very minimal just for
watching a set of PMCs (counter mode, not sample mode) just for this particular
setup.  But it's enough to at least get the thing to work.
Bring in the very basic pmc configuration.

This is a very simple, static PMC setup.  It's also very hacky.
But it's enough to verify that this is actually working.
Sure enough, instruction counters are spat out.
* Add in pmcstat_pmc.[ch] - oops, forgot. This now doesn't use pmcstat.c;
  it uses its own code
* Don't compile in pmcstat.[ch]
Remove pmcstat.[ch]; no longer needed.