ARM: dts: rockchip: set the pinctrl default setting for rk3036 i2s

Sometime will hang if you set the i2s pinctrl as the none setting.
Let's set the pinctrl as the default setting to enable the gpio bias.

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>