The libuinet pcpu subsystem can usefully be initialized with any
number of cpus less than or equal to the number of host cpus, and when
initialized with less than the number of host cpus, it is possible for
threads to be pinned to cpus beyond the set that the libuinet pcpu
subsystem is aware of.  This patch ensures that threads pinned to host
cpus beyond the set of cpus the libuinet pcpu susbsystem is aware of
are mapped into the available pcpu state set.