gpio: davinci: Make irq_chip immutable

Kernel warns about mutable irq_chips:
"not an immutable chip, please consider fixing!"

Constify gpio_irqchip, flag the irq_chip as IRQCHIP_IMMUTABLE, add the
new helper functions, and call the appropriate gpiolib functions.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250509-gpio-v1-6-639377c98288@nxp.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: MrVan

drivers/gpio/gpio-davinci.c

@@ -253,6 +253,8 @@ static void gpio_irq_mask(struct irq_data *d)
 
 	writel_relaxed(mask, &g->clr_falling);
 	writel_relaxed(mask, &g->clr_rising);
+
+	gpiochip_disable_irq(&chips->chip, hwirq);
 }
 
 static void gpio_irq_unmask(struct irq_data *d)
@@ -263,6 +265,8 @@ static void gpio_irq_unmask(struct irq_data *d)
 	uintptr_t mask = (uintptr_t)irq_data_get_irq_handler_data(d);
 	unsigned status = irqd_get_trigger_type(d);
 
+	gpiochip_enable_irq(&chips->chip, hwirq);
+
 	status &= IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING;
 	if (!status)
 		status = IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING;
@@ -281,12 +285,13 @@ static int gpio_irq_type(struct irq_data *d, unsigned trigger)
 	return 0;
 }
 
-static struct irq_chip gpio_irqchip = {
+static const struct irq_chip gpio_irqchip = {
 	.name		= "GPIO",
 	.irq_unmask	= gpio_irq_unmask,
 	.irq_mask	= gpio_irq_mask,
 	.irq_set_type	= gpio_irq_type,
-	.flags		= IRQCHIP_SET_TYPE_MASKED | IRQCHIP_SKIP_SET_WAKE,
+	.flags		= IRQCHIP_IMMUTABLE | IRQCHIP_SET_TYPE_MASKED | IRQCHIP_SKIP_SET_WAKE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 static void gpio_irq_handler(struct irq_desc *desc)