[U-Boot] rockchip: dts: fix unnecessary '-cells' warning

[Philipp Tomsich]

> Fix warning below:
> unnecessary #address-cells/#size-cells without "ranges" or child "reg"
> property
> 
> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
> Reviewed-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> ---
> 
>  arch/arm/dts/rk3288-evb.dtsi     | 2 --
>  arch/arm/dts/rk3288-firefly.dtsi | 2 --
>  arch/arm/dts/rk3288-tinker.dtsi  | 2 --
>  arch/arm/dts/rk3288-veyron.dtsi  | 2 --
>  arch/arm/dts/rk3288.dtsi         | 2 --
>  arch/arm/dts/rk3328.dtsi         | 2 --
>  arch/arm/dts/rk3399-puma.dtsi    | 2 --
>  arch/arm/dts/rk3399.dtsi         | 4 ----
>  8 files changed, 18 deletions(-)
> 

Acked-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>