mfd: tps65910: Constify struct regmap_irq_chip

`tps65910_irq_chip` and `tps65911_irq_chip` are not modified and can be
declared as const to move their data to a read-only section.

The pointer used to reference those structs has also been converted to
const.

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

drivers/mfd/tps65910.c

···
 	},
 };
 
-static struct regmap_irq_chip tps65911_irq_chip = {
+static const struct regmap_irq_chip tps65911_irq_chip = {
 	.name = "tps65910",
 	.irqs = tps65911_irqs,
 	.num_irqs = ARRAY_SIZE(tps65911_irqs),
···
 	.ack_base = TPS65910_INT_STS,
 };
 
-static struct regmap_irq_chip tps65910_irq_chip = {
+static const struct regmap_irq_chip tps65910_irq_chip = {
 	.name = "tps65910",
 	.irqs = tps65910_irqs,
 	.num_irqs = ARRAY_SIZE(tps65910_irqs),
···
 		    struct tps65910_platform_data *pdata)
 {
 	int ret;
-	static struct regmap_irq_chip *tps6591x_irqs_chip;
+	static const struct regmap_irq_chip *tps6591x_irqs_chip;
 
 	if (!irq) {
 		dev_warn(tps65910->dev, "No interrupt support, no core IRQ\n");