dt-bindings: gpio: rockchip: add gpio-ranges

Allow usage of gpio-ranges with the rockchip gpio controller. The driver
already had support for this since it has been added to the mainline kernel
in the first place.

Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>
Reviewed-by: Heiko Stuebner <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
Signed-off-by: Bartosz Golaszewski <[e-mail]>

Documentation/devicetree/bindings/gpio/rockchip,gpio-bank.yaml

···
       - description: APB interface clock source
       - description: GPIO debounce reference clock source
 
+  gpio-ranges: true
+
   gpio-controller: true
 
   gpio-line-names: true