pinctrl: sunxi: constify irq_domain_ops

struct irq_domain_ops is not modified, so it can be made const.
Suggested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/sunxi/pinctrl-sunxi.c

@@ -979,7 +979,7 @@ static int sunxi_pinctrl_irq_of_xlate(struct irq_domain *d,
 	return 0;
 }
 
-static struct irq_domain_ops sunxi_pinctrl_irq_domain_ops = {
+static const struct irq_domain_ops sunxi_pinctrl_irq_domain_ops = {
 	.xlate		= sunxi_pinctrl_irq_of_xlate,
 };