gpio: uniphier: Fix void functions to remove return value

The return type of irq_chip.irq_mask() and irq_chip.irq_unmask() should
be void.

Fixes: dbe776c2 ("gpio: uniphier: add UniPhier GPIO controller driver")
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

drivers/gpio/gpio-uniphier.c

@@ -184,7 +184,7 @@ static void uniphier_gpio_irq_mask(struct irq_data *data)
 
 	uniphier_gpio_reg_update(priv, UNIPHIER_GPIO_IRQ_EN, mask, 0);
 
-	return irq_chip_mask_parent(data);
+	irq_chip_mask_parent(data);
 }
 
 static void uniphier_gpio_irq_unmask(struct irq_data *data)
@@ -194,7 +194,7 @@ static void uniphier_gpio_irq_unmask(struct irq_data *data)
 
 	uniphier_gpio_reg_update(priv, UNIPHIER_GPIO_IRQ_EN, mask, mask);
 
-	return irq_chip_unmask_parent(data);
+	irq_chip_unmask_parent(data);
 }
 
 static int uniphier_gpio_irq_set_type(struct irq_data *data, unsigned int type)