kernel FDT is for U-Boot if there is not valid one from images,
ie: resource.img, boot.img or recovery.img. It is put right
after U-Boot FDT.
This is used for U-disk bing up.
Signed-off-by: Joseph Chen <chenjh@rock-chips.com>
Change-Id: I348b6ea5736f46c091284c501e7e0f9c64cd2f78