binman: Support adding files

In some cases it is useful to add a group of files to the image and be
able to access them at run-time. Of course it is possible to generate
the binman config file with a set of blobs each with a filename. But for
convenience, add an entry type which can do this.

Add required support (for adding nodes and string properties) into the
state module.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/binman/control.py

@@ -146,6 +146,7 @@ def Binman(options, args):
             # without changing the device-tree size, thus ensuring that our
             # entry offsets remain the same.
             for image in images.values():
+                image.ExpandEntries()
                 if options.update_fdt:
                     image.AddMissingProperties()
                 image.ProcessFdt(dtb)