genirq: Export irq_gc_noop()

In order to build drivers/irqchip/irq-bcm7120-l2.c as a module which
references irq_gc_noop(), we need to export it towards modules.

Signed-off-by: Florian Fainelli <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

kernel/irq/generic-chip.c

···
 void irq_gc_noop(struct irq_data *d)
 {
 }
+EXPORT_SYMBOL_GPL(irq_gc_noop);
 
 /**
  * irq_gc_mask_disable_reg - Mask chip via disable register