bring mk908 dts in line with recent structural changes
rk3xxx.dtsi: remove inclusion of cru header
ARM: dts: rockchip: remove pinctrl setting from radxarock uart2

We set default pinctrl settings for the uarts in rk3188.dtsi already,
so remove forgotten duplicate.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>