gpio: em: 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>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-em.c

@@ -337,8 +337,6 @@ static int em_gio_probe(struct platform_device *pdev)
 	irq_chip->name = name;
 	irq_chip->irq_mask = em_gio_irq_disable;
 	irq_chip->irq_unmask = em_gio_irq_enable;
-	irq_chip->irq_enable = em_gio_irq_enable;
-	irq_chip->irq_disable = em_gio_irq_disable;
 	irq_chip->irq_set_type = em_gio_irq_set_type;
 	irq_chip->flags	= IRQCHIP_SKIP_SET_WAKE;