arm64: dts: enable pinctrl for Broadcom NS2 SoC

This enables the pinctrl support for Broadcom NS2 SoC

Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>