mfd: tps65912: Constify struct regmap_irq_chip

`tps65912_irq_chip` is not modified and can be declared as const to
move its data to a read-only section.
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20240704-mfd-const-regmap_config-v2-20-0c8785b1331d@gmail.comSigned-off-by: Lee Jones <lee@kernel.org>

drivers/mfd/tps65912-core.c

@@ -57,7 +57,7 @@ static const struct regmap_irq tps65912_irqs[] = {
 	REGMAP_IRQ_REG(TPS65912_IRQ_PGOOD_LDO10, 3, TPS65912_INT_STS4_PGOOD_LDO10),
 };
 
-static struct regmap_irq_chip tps65912_irq_chip = {
+static const struct regmap_irq_chip tps65912_irq_chip = {
 	.name = "tps65912",
 	.irqs = tps65912_irqs,
 	.num_irqs = ARRAY_SIZE(tps65912_irqs),