gpio: unmap gpio irqs properly

When using the irqchip helper inside the gpiolib, make sure
the IRQs are unmapped/disposed before the irqdomain is removed
as part of removing the gpiochip.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --cc drivers/gpio/gpiolib.c
Simple merge

diff --cc include/linux/gpio/driver.h
Simple merge