The driver accesses the of_node field of struct gpio_chip, which is only
available if OF_GPIO is selected. This solves a build issue on SPARC
which conflicts with OF_GPIO and therefore does not provide this field.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>