sched/topology: Fix sched_numa_find_nth_cpu() in non-NUMA case

When CONFIG_NUMA is enabled, sched_numa_find_nth_cpu() searches for a
CPU in sched_domains_numa_masks. The masks includes only online CPUs,
so effectively offline CPUs are skipped.

When CONFIG_NUMA is disabled, the fallback function should be consistent.

Fixes: cd7f55359c90 ("sched: add sched_numa_find_nth_cpu()")
Signed-off-by: Yury Norov <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>
Cc: Mel Gorman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

include/linux/topology.h

···
 #else
 static __always_inline int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node)
 {
-	return cpumask_nth(cpu, cpus);
+	return cpumask_nth_and(cpu, cpus, cpu_online_mask);
 }
 
 static inline const struct cpumask *