binman: add tests for sign option

Add the test which provides sequence of actions:
  1. create the image from binman dts
  2. create public and private keys
  3. add public key into dtb with fdt_add_pubkey
  4. 1. sign FIT container with new sign option with extracting from
        image
     2. sign exact FIT container with replacing of it in image
  5. check with fit_check_sign

Signed-off-by: Ivan Mikhaylov <fr0st61te@gmail.com>
Renumber test file from 277 to 280;
   Move UpdateSignatures() to Entry base class;
   Don't allow missing mkimage as it doesn't make sense;
   Propagate --toolpath for CI;
   Call mark_build_done() to avoid regenerating FIT:
Signed-off-by: Simon Glass <sjg@chromium.org>

tools/binman/control.py

@@ -464,6 +464,8 @@ def SignEntries(image_fname, input_fname, privatekey_fname, algo, entry_paths,
     image_fname = os.path.abspath(image_fname)
     image = Image.FromFile(image_fname)
 
+    image.mark_build_done()
+
     BeforeReplace(image, allow_resize=True)
 
     for entry_path in entry_paths: