mfd: Fix building without CONFIG_OF

Using the of_fwnode_handle() means that local 'node' variables are unused
whenever CONFIG_OF is disabled for compile testing:

drivers/mfd/88pm860x-core.c: In function 'device_irq_init':
drivers/mfd/88pm860x-core.c:576:29: error: unused variable 'node' [-Werror=unused-variable]
576 | struct device_node *node = i2c->dev.of_node;
| ^~~~
drivers/mfd/max8925-core.c: In function 'max8925_irq_init':
drivers/mfd/max8925-core.c:659:29: error: unused variable 'node' [-Werror=unused-variable]
659 | struct device_node *node = chip->dev->of_node;
| ^~~~
drivers/mfd/twl4030-irq.c: In function 'twl4030_init_irq':
drivers/mfd/twl4030-irq.c:679:46: error: unused variable 'node' [-Werror=unused-variable]
679 | struct device_node *node = dev->of_node;
| ^~~~

Replace these with the corresponding dev_fwnode() lookups that
keep the code simpler in addition to avoiding the warnings.

Fixes: e3d44f11da04 ("mfd: Switch to irq_domain_create_*()")
Signed-off-by: Arnd Bergmann <[e-mail]>
Reviewed-by: Jiri Slaby <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/88pm860x-core.c

···
 	unsigned long flags = IRQF_TRIGGER_FALLING | IRQF_ONESHOT;
 	int data, mask, ret = -EINVAL;
 	int nr_irqs, irq_base = -1;
-	struct device_node *node = i2c->dev.of_node;
 
 	mask = PM8607_B0_MISC1_INV_INT | PM8607_B0_MISC1_INT_CLEAR
 		| PM8607_B0_MISC1_INT_MASK;
···
 		ret = -EBUSY;
 		goto out;
 	}
-	irq_domain_create_legacy(of_fwnode_handle(node), nr_irqs, chip->irq_base, 0,
+	irq_domain_create_legacy(dev_fwnode(&i2c->dev), nr_irqs, chip->irq_base, 0,
 				 &pm860x_irq_domain_ops, chip);
 	chip->core_irq = i2c->irq;
 	if (!chip->core_irq)

drivers/mfd/max8925-core.c

···
 {
 	unsigned long flags = IRQF_TRIGGER_FALLING | IRQF_ONESHOT;
 	int ret;
-	struct device_node *node = chip->dev->of_node;
 
 	/* clear all interrupts */
 	max8925_reg_read(chip->i2c, MAX8925_CHG_IRQ1);
···
 		return -EBUSY;
 	}
 
-	irq_domain_create_legacy(of_fwnode_handle(node), MAX8925_NR_IRQS, chip->irq_base, 0,
-				 &max8925_irq_domain_ops, chip);
+	irq_domain_create_legacy(dev_fwnode(chip->dev), MAX8925_NR_IRQS,
+				 chip->irq_base, 0, &max8925_irq_domain_ops,
+				 chip);
 
 	/* request irq handler for pmic main irq*/
 	chip->core_irq = irq;

drivers/mfd/twl4030-irq.c

···
 	static struct irq_chip	twl4030_irq_chip;
 	int			status, i;
 	int			irq_base, irq_end, nr_irqs;
-	struct			device_node *node = dev->of_node;
 
 	/*
 	 * TWL core and pwr interrupts must be contiguous because
···
 		return irq_base;
 	}
 
-	irq_domain_create_legacy(of_fwnode_handle(node), nr_irqs, irq_base, 0,
+	irq_domain_create_legacy(dev_fwnode(dev), nr_irqs, irq_base, 0,
 				 &irq_domain_simple_ops, NULL);
 
 	irq_end = irq_base + TWL4030_CORE_NR_IRQS;