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/stmpe.c b/drivers/mfd/stmpe.c
index 2d7fae9..18c4d72 100644
--- a/drivers/mfd/stmpe.c
+++ b/drivers/mfd/stmpe.c
@@ -989,7 +989,7 @@
 		irq_set_chip_data(virq, NULL);
 }
 
-static struct irq_domain_ops stmpe_irq_ops = {
+static const struct irq_domain_ops stmpe_irq_ops = {
         .map    = stmpe_irq_map,
         .unmap  = stmpe_irq_unmap,
         .xlate  = irq_domain_xlate_twocell,