gpio: pxa: Make irq_chip immutable

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

Constify pxa_muxed_gpio_chip, 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-v1-9-639377c98288@nxp.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: MrVan

drivers/gpio/gpio-pxa.c

@@ -497,6 +497,8 @@ static void pxa_mask_muxed_gpio(struct irq_data *d)
 	gfer = readl_relaxed(base + GFER_OFFSET) & ~GPIO_bit(gpio);
 	writel_relaxed(grer, base + GRER_OFFSET);
 	writel_relaxed(gfer, base + GFER_OFFSET);
+
+	gpiochip_disable_irq(&pchip->chip, gpio);
 }
 
 static int pxa_gpio_set_wake(struct irq_data *d, unsigned int on)
@@ -516,17 +518,21 @@ static void pxa_unmask_muxed_gpio(struct irq_data *d)
 	unsigned int gpio = irqd_to_hwirq(d);
 	struct pxa_gpio_bank *c = gpio_to_pxabank(&pchip->chip, gpio);
 
+	gpiochip_enable_irq(&pchip->chip, gpio);
+
 	c->irq_mask |= GPIO_bit(gpio);
 	update_edge_detect(c);
 }
 
-static struct irq_chip pxa_muxed_gpio_chip = {
+static const struct irq_chip pxa_muxed_gpio_chip = {
 	.name		= "GPIO",
 	.irq_ack	= pxa_ack_muxed_gpio,
 	.irq_mask	= pxa_mask_muxed_gpio,
 	.irq_unmask	= pxa_unmask_muxed_gpio,
 	.irq_set_type	= pxa_gpio_irq_type,
 	.irq_set_wake	= pxa_gpio_set_wake,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 static int pxa_gpio_nums(struct platform_device *pdev)