[U-Boot] rockchip: rk3328: correct mem_region

[Philipp Tomsich]

> According to rk3328 TRM:
> 0~0xff000000 is ddr space;
> 0xff000000~0xffffffff is device space.
> 
> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> ---
> 
>  arch/arm/mach-rockchip/rk3328/rk3328.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 

Applied to u-boot-rockchip/next, thanks!