dt-bindings: pinctrl: rockchip: add RK3568 SoC support

Add RK3568/RK3566 SoC support to pinctrl.
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210410204500.18091-1-ezequiel@collabora.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/rockchip,pinctrl.txt

@@ -33,6 +33,7 @@ Required properties for iomux controller:
 		"rockchip,rk3328-pinctrl":  for Rockchip RK3328
 		"rockchip,rk3368-pinctrl":  for Rockchip RK3368
 		"rockchip,rk3399-pinctrl":  for Rockchip RK3399
+		"rockchip,rk3568-pinctrl":  for Rockchip RK3568
 
   - rockchip,grf: phandle referencing a syscon providing the
 	 "general register files"