gpio: pl061: hook request if gpio-ranges avaiable

Gpio-ranges property is useful to represent which GPIOs correspond
to which pins on which pin controllers. But there may be some gpios
without pinctrl operation. So check whether gpio-ranges property
exists in device node first.

Signed-off-by: Yunlei He <heyunlei@huawei.com>
Signed-off-by: Xinwei Kong <kong.kongxinwei@hisilicon.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>