[U-Boot] rockchip: rk3399-puma: reduce env size to 8kiB

[Philipp Tomsich]

On Thu, 21 Dec 2017, Jakob Unterwurzacher wrote:

> ...even when the environment is saved to SD card.

Please don't start a commit message with an ellipsis, but rather
with a regular sentence.

I'll fix this, when I apply the patch (... this time).

>
> With the default of 32kiB, the environment overwrites the SPL
> stage which lives at 16kiB.
>
> Signed-off-by: Jakob Unterwurzacher <jakob.unterwurzacher at theobroma-systems.com>
> Acked-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>

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