gpio: Move irqdomain into struct gpio_irq_chip

In order to consolidate the multiple ways to associate an IRQ chip with
a GPIO chip, move more fields into the new struct gpio_irq_chip.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-intel-mid.c b/drivers/gpio/gpio-intel-mid.c
index b76ecee..629575e 100644
--- a/drivers/gpio/gpio-intel-mid.c
+++ b/drivers/gpio/gpio-intel-mid.c
@@ -295,7 +295,7 @@ static void intel_mid_irq_handler(struct irq_desc *desc)
 			mask = BIT(gpio);
 			/* Clear before handling so we can't lose an edge */
 			writel(mask, gedr);
-			generic_handle_irq(irq_find_mapping(gc->irqdomain,
+			generic_handle_irq(irq_find_mapping(gc->irq.domain,
 							    base + gpio));
 		}
 	}