Accept the documented FDT compatible string for the PL310 cache controller
as well as the non-standard string we've been using for a couple years.
Correct my previous commit:

- getrusage_utime_back succeeds reliably on FreeBSD
- getrusage_utime_zero passes/fails in a seemingly non-deterministic manner.
  Skip it for now (and fix it later)

In the initial port of this testcase to FreeBSD, the results failed reliably
in the same manner as it does on NetBSD

Sponsored by: EMC / Isilon Storage Division
- Add sys/types.h for the APIs in sys/sysctl.h
- Poke at VM_MIN_ADDRESS in machine/vmparam.h because FreeBSD doesn't have a
  vm.minaddress sysctl analog
- Expect ENOMEM instead of EAGAIN in mlock_limits
- Provide mlock an mmap'ed page twice to simulate MAP_WIRED on NetBSD

In collaboration with: pho
Sponsored by: EMC / Isilon Storage Division