gpio: select IRQ_DOMAIN for gpiolib irqchip helpers

These helpers depend on the IRQ_DOMAIN so select it explicitly,
as it will not be present on all platforms such as Intel
desktops and laptops using Intel-MID.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index fa3cb18..4a1b511 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -56,6 +56,7 @@
 	depends on ACPI
 
 config GPIOLIB_IRQCHIP
+	select IRQ_DOMAIN
 	bool
 
 config DEBUG_GPIO
@@ -710,7 +711,7 @@
 config GPIO_INTEL_MID
 	bool "Intel Mid GPIO support"
 	depends on PCI && X86
-	select IRQ_DOMAIN
+	select GPIOLIB_IRQCHIP
 	help
 	  Say Y here to support Intel Mid GPIO.