gpio: implement gpio-ranges binding document fix

Use the new of_parse_phandle_with_fixed_args() to implement the
corrected gpio-ranges DT property definition.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@linaro.org>