Prevent flashing truncated or otherwise corrupted uImage.FIT images
by verifying checksums and hashes of all sub-images before flashing
using the newly packaged fit_check_sign tool.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Move shell functions used for sysupgrade into /lib/upgrade/fit.sh.
Introduce improved fitblk boot device detection function which
works also in case ubiblock devices have not yet been created or
even UBI itself not yet being attached.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>