The current code doesn't check if GPIOLIB_IRQCHIP is enabled, which results in
a compilation error when trying to build gpio-regmap if CONFIG_GPIOLIB_IRQCHIP
isn't enabled.
Fixes: 6a45b0e2589f ("gpiolib: Introduce gpiochip_irqchip_add_domain()")
Suggested-by: Michael Walle <michael@xxxxxxxx>
Signed-off-by: Álvaro Fernández Rojas <noltari@xxxxxxxxx>