irqchip: renesas-irqc: Use lazy disable

Set the ->irq_enable() and ->irq_disable() methods to NULL
to enable lazy disable of interrupts. This by itself provides
some level of optimization, but is mainly enabled as ground
work for future Suspend-to-RAM wake up support.
Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

drivers/irqchip/irq-renesas-irqc.c

@@ -212,8 +212,6 @@ static int irqc_probe(struct platform_device *pdev)
 	irq_chip->name = name;
 	irq_chip->irq_mask = irqc_irq_disable;
 	irq_chip->irq_unmask = irqc_irq_enable;
-	irq_chip->irq_enable = irqc_irq_enable;
-	irq_chip->irq_disable = irqc_irq_disable;
 	irq_chip->irq_set_type = irqc_irq_set_type;
 	irq_chip->flags	= IRQCHIP_SKIP_SET_WAKE;