irqdomain: Check for NULL function pointer in irq_domain_free_irqs_hierarchy()

A follow-on patch will call irq_domain_free_irqs_hierarchy() when the
free() function pointer may be NULL.

Add a NULL pointer check to handle this new use case.

Signed-off-by: David Daney <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Marc Zyngier <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Alexandre Courbot <[email protected]>
Cc: Linus Walleij <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]

Author: daviddaney

kernel/irq/irqdomain.c

@@ -1362,7 +1362,8 @@ static void irq_domain_free_irqs_hierarchy(struct irq_domain *domain,
 					   unsigned int irq_base,
 					   unsigned int nr_irqs)
 {
-	domain->ops->free(domain, irq_base, nr_irqs);
+	if (domain->ops->free)
+		domain->ops->free(domain, irq_base, nr_irqs);
 }
 
 int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,