test_vboot.py: include test of fdt_add_pubkey tool

Add test_fdt_add_pubkey test which provides simple functionality test
which contains such steps:
 create DTB and FIT files
 add keys with fdt_add_pubkey to DTB
 sign FIT image
 check with fit_check_sign that keys properly added to DTB file

Signed-off-by: Roman Kopytin <Roman.Kopytin@kaspersky.com>
Signed-off-by: Ivan Mikhaylov <fr0st61te@gmail.com>
Cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
1 file changed