regmap: Constify irq_domain_ops

The irq_domain_ops are not modified by the driver and the irqdomain core
code accepts pointer to a const data.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regmap-irq.c

@@ -318,7 +318,7 @@ static int regmap_irq_map(struct irq_domain *h, unsigned int virq,
 	return 0;
 }
 
-static struct irq_domain_ops regmap_domain_ops = {
+static const struct irq_domain_ops regmap_domain_ops = {
 	.map	= regmap_irq_map,
 	.xlate	= irq_domain_xlate_twocell,
 };