tools: Add preload_check_sign to authenticate images with a pre-load

preload_check_sign is added so that it can be used to authenticate images
signed with the pre-load signature supported by binman and U-Boot.
It could also be used to test the signature in binman tests signing
images with the pre-load.

Signed-off-by: Paul HENRYS <paul.henrys_ext@softathome.com>
4 files changed