This patch adds the device tree bindings for the Western Digital's
MyBook Live memory-mapped GPIO controllers.

The gpios will be supported by gpio-mmio code of the
GPIO generic library.
Signed-off-by: NChristian Lamparter <chunkeey@googlemail.com>
Acked-by: NRob Herring <robh@kernel.org>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>