Move some definitions from u-boot.inc into uboot-config.bbclass and
similarly from kernel-fitimage.bbclass into uboot-sign.bbclass, so that
they can be useful when signing the U-boot proper fitimage, for a
verified-boot SPL.
(From OE-Core rev: cc6c3e31526d3b6ef3a87ba5e548fcad7483bd51)
Signed-off-by: Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>