genirq/cpuhotplug: Dont claim success on error

In case the affinity of an interrupt was broken, a printk is emitted.

But if the affinity cannot be set at all due to a missing
irq_set_affinity() callback or due to a failing callback, the message is
still printed preceeded by a warning/error.

That makes no sense whatsoever.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235445.274852976@linutronix.de

kernel/irq/cpuhotplug.c

@@ -37,11 +37,14 @@ static bool migrate_one_irq(struct irq_desc *desc)
 	c = irq_data_get_irq_chip(d);
 	if (!c->irq_set_affinity) {
 		pr_debug("IRQ%u: unable to set affinity\n", d->irq);
+		ret = false;
 	} else {
 		int r = irq_do_set_affinity(d, affinity, false);
-		if (r)
+		if (r) {
 			pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n",
 					    d->irq, r);
+			ret = false;
+		}
 	}
 
 	return ret;