mfd: 88pm80x: Constify read-only regmap structs

`pm800_irq`, `pm805_irq` and `pm805_irq_chip` are not modified and can
be declared as const to move their data to a read-only section.

In order to keep the const modifier for the regmap_irq_chip structures,
the pointer used to reference them must be converted to const as well.

Signed-off-by: Javier Carrasco <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/88pm800.c

···
 	regmap_del_irq_chip(chip->irq, chip->irq_data);
 }
 
-static struct regmap_irq_chip pm800_irq_chip = {
+static const struct regmap_irq_chip pm800_irq_chip = {
 	.name = "88pm800",
 	.irqs = pm800_irqs,
 	.num_irqs = ARRAY_SIZE(pm800_irqs),

drivers/mfd/88pm805.c

···
 	 },
 };
 
-static struct regmap_irq pm805_irqs[] = {
+static const struct regmap_irq pm805_irqs[] = {
 	/* INT0 */
 	[PM805_IRQ_LDO_OFF] = {
 		.mask = PM805_INT1_HP1_SHRT,
···
 	regmap_del_irq_chip(chip->irq, chip->irq_data);
 }
 
-static struct regmap_irq_chip pm805_irq_chip = {
+static const struct regmap_irq_chip pm805_irq_chip = {
 	.name = "88pm805",
 	.irqs = pm805_irqs,
 	.num_irqs = ARRAY_SIZE(pm805_irqs),

include/linux/mfd/88pm80x.h

···
 	struct i2c_client *client;
 	struct i2c_client *companion;
 	struct regmap *regmap;
-	struct regmap_irq_chip *regmap_irq_chip;
+	const struct regmap_irq_chip *regmap_irq_chip;
 	struct regmap_irq_chip_data *irq_data;
 	int type;
 	int irq;