SMP: Enforce this rule: Tasks which are normally restored when sched_unlock()...

SMP: Enforce this rule: Tasks which are normally restored when sched_unlock() is called must remain pending (1) if we are in a critical section, i.e., g_cpu_irqlock is locked , or (2) other CPUs still have pre-emption disabled, i.e., g_cpu_schedlock is locked.  In those cases, the release of the pending tasks must be deferred until those conditions are met.