This makes the driver use the irqchip template to assign
properties to the gpio_irq_chip instead of using the
explicit calls to gpiochip_irqchip_add(). The irqchip is
instead added while adding the gpiochip.
Cc: Eudean Sun <eudean@arista.com> Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com> Cc: Sébastien Szymanski <sebastien.szymanski@armadeus.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>