sparseirq: fix numa_migrate_irq_desc dependency and comments

Impact: reduce kconfig variable scope and clean up

Bartlomiej pointed out that the config dependencies and comments are not right.

update it depend to NUMA, and fix some comments

Reported-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/io_apic.c

@@ -2471,7 +2471,7 @@ static void irq_complete_move(struct irq_desc **descp)
 		if (likely(!cfg->move_desc_pending))
 			return;
 
-		/* domain is not change, but affinity is changed */
+		/* domain has not changed, but affinity did */
 		me = smp_processor_id();
 		if (cpu_isset(me, desc->affinity)) {
 			*descp = desc = move_irq_desc(desc, me);