class: add creation of fit-image for secure boot
class: add creation of fit-image for secure boot

The Flattened Image Tree (FIT) format is already widely used in u-boot and Barebox.
It is a flattened device tree (FDT) in a particular format with images contained within.
FITs include hashes to verify images, so it is relatively straightforward to add
signatures as well.

Signed-off-by: Maik Otto <02e78f91e4f91b159cf17d6f461d36832c8f774b@phytec.de>
Signed-off-by: Stefan Müller-Klieser <a3e08e35e4a42be768e7d0e76ae1ba321c2a66dd@phytec.de>

PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec