mfd: Constify regmap and irq configuration data

Constify in various drivers configuration data which is not modified:
 - regmap_irq_chip,
 - individual regmap_irq's in array,
 - regmap_config,
 - irq_domain_ops,

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/arizona-irq.c b/drivers/mfd/arizona-irq.c
index d063b94..2b9965d5 100644
--- a/drivers/mfd/arizona-irq.c
+++ b/drivers/mfd/arizona-irq.c
@@ -186,7 +186,7 @@
 	return 0;
 }
 
-static struct irq_domain_ops arizona_domain_ops = {
+static const struct irq_domain_ops arizona_domain_ops = {
 	.map	= arizona_irq_map,
 	.xlate	= irq_domain_xlate_twocell,
 };