gpio: Remove unused 'irqchip' argument to gpiochip_set_cascaded_irqchip()

This argument hasn't ever been used since it was introduced in commit
14250520 ("gpio: add IRQ chip helpers in gpiolib"). Let's drop it to
reduce reading confusion.

Cc: Evan Green <evgreen@chromium.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib.c

@@ -1663,7 +1663,6 @@ EXPORT_SYMBOL_GPL(gpiochip_irqchip_irq_valid);
 /**
  * gpiochip_set_cascaded_irqchip() - connects a cascaded irqchip to a gpiochip
  * @gpiochip: the gpiochip to set the irqchip chain to
- * @irqchip: the irqchip to chain to the gpiochip
  * @parent_irq: the irq number corresponding to the parent IRQ for this
  * chained irqchip
  * @parent_handler: the parent interrupt handler for the accumulated IRQ
@@ -1671,7 +1670,6 @@ EXPORT_SYMBOL_GPL(gpiochip_irqchip_irq_valid);
  * cascaded, pass NULL in this handler argument
  */
 static void gpiochip_set_cascaded_irqchip(struct gpio_chip *gpiochip,
-					  struct irq_chip *irqchip,
 					  unsigned int parent_irq,
 					  irq_flow_handler_t parent_handler)
 {
@@ -1719,8 +1717,7 @@ void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
 		return;
 	}
 
-	gpiochip_set_cascaded_irqchip(gpiochip, irqchip, parent_irq,
-				      parent_handler);
+	gpiochip_set_cascaded_irqchip(gpiochip, parent_irq, parent_handler);
 }
 EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip);
 
@@ -1735,8 +1732,7 @@ void gpiochip_set_nested_irqchip(struct gpio_chip *gpiochip,
 				 struct irq_chip *irqchip,
 				 unsigned int parent_irq)
 {
-	gpiochip_set_cascaded_irqchip(gpiochip, irqchip, parent_irq,
-				      NULL);
+	gpiochip_set_cascaded_irqchip(gpiochip, parent_irq, NULL);
 }
 EXPORT_SYMBOL_GPL(gpiochip_set_nested_irqchip);