irqdomain: Fix irq_domain_alloc_irqs_recursive() error handling

If an irq_domain is auto-recursive and irq_domain_alloc_irqs_recursive()
for its parent has returned an error, then do return and avoid calling
irq_domain_free_irqs_recursive() uselessly, because:
- if domain->ops->alloc() had failed for an auto-recursive irq_domain,
   then irq_domain_free_irqs_recursive() had already been called;
- if domain->ops->alloc() had failed for a not auto-recursive irq_domain,
   then there is nothing to free at all.

Signed-off-by: Alexander Popov <alex.popov@linux.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/1467505448-2850-1-git-send-email-alex.popov@linux.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/irq/irqdomain.c

@@ -1192,8 +1192,10 @@ int irq_domain_alloc_irqs_recursive(struct irq_domain *domain,
 	if (recursive)
 		ret = irq_domain_alloc_irqs_recursive(parent, irq_base,
 						      nr_irqs, arg);
-	if (ret >= 0)
-		ret = domain->ops->alloc(domain, irq_base, nr_irqs, arg);
+	if (ret < 0)
+		return ret;
+
+	ret = domain->ops->alloc(domain, irq_base, nr_irqs, arg);
 	if (ret < 0 && recursive)
 		irq_domain_free_irqs_recursive(parent, irq_base, nr_irqs);