[U-Boot] rockchip: rk3399-puma: preserve leading zeros in serial#

[Philipp Tomsich]

> Linux preserves leading zeros in /proc/cpuinfo, so we
> should as well.
> 
> Otherwise we have the situation that
> /sys/firmware/devicetree/base/serial-number
> and /proc/cpuinfo disagree in Linux.
> 
> Signed-off-by: Jakob Unterwurzacher <jakob.unterwurzacher at theobroma-systems.com>
> Reviewed-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> ---
> 
>  board/theobroma-systems/puma_rk3399/puma-rk3399.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 

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