Now that quiescent states for newly offlined CPUs are reported either
when that CPU goes offline or at the end of grace-period initialization,
the CPU-hotplug failsafe in the force-quiescent-state code path is no
longer needed.

This commit therefore removes this failsafe.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>