[U-Boot] [U-Boot, 2/3] rockchip: rk3399: enable fastboot to set boot mode tag

[Philipp Tomsich]

> fastboot have a command "reboot-bootloader" which require the boot
> loader to reboot and get into fastboot mode again.
> 
> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> ---
> 
>  arch/arm/mach-rockchip/rk3399/rk3399.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 

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