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>
diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index a6c3f75..e7273bb 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -318,7 +318,7 @@
 	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,
 };