uboot-phytec

rockchip: Add support for rk's second level loader

The Rockchip boot ROM could load & run an initial spl loader,
and continue to load a second level boot-loader(which stored
right after the initial loader) when it returns.
Modify idblock generation code to support it.

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>