[U-Boot] rockchip: Fix rkimage format for SPL boot over USB

[Philipp Tomsich]

> The 'rkimage' format used for booting rockchip boards over USB seems to
> have been broken since commit 7bf274b9caab ("rockchip: mkimage: use
> imagename to select spl hdr & spl size"). That commit adds an offset of
> RK_SPL_HDR_START(=2048) to the location the 'RKxx' header is written
> at. However the bootrom expects this header to be the first four bytes of
> the image, not at offset 2048. This appears to have been a copy paste
> error since the 'rksd' and 'rkspi' image types do require this offset.
> 
> Furthermore commit 111bcc4fb6cb ("rockchip: mkimage: pad the header to
> 8-bytes (using a 'nop') for RK3399"), commit 3d54eabcafec9 ("rockchip:
> spl: RK3399: use boot0 hook to create space for SPL magic") and
> commit 308277569229 ("rockchip: mkimage: update rkimage to support
> pre-padded payloads") changed the way the space for the 'RKxx' header is
> allocated and written to the image without adjusting 'rkimage'.
> 
> This commit fixes those mistakes and makes it possible to load u-boot SPL
> over USB once more.
> 
> (Tested on RK3399)
> 
> Signed-off-by: Daniel Gröber <daniel at dps.uibk.ac.at>
> Reviewed-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> ---
> 
>  tools/rkimage.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 

Applied to u-boot-rockchip, thanks!