commit 01cca93a upstream.

Unregister gpiochip device (used to export information through sysfs)
before removing it internally. This way removal will reverse addition.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>