We need to convert all old gpio irqchips to pass the irqchip
setup along when adding the gpio_chip. For more info see
drivers/gpio/TODO.

For chained irqchips this is a pretty straight-forward
conversion. This driver requests the IRQ directly in the driver
so it needs to pass a NULL parent handler. We may revisit this
code later and pull reqular shared IRQ handler into
gpiolib, so leave a FIXME.

Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>