Some boards need to load an ELF file using the 'loadables' property, but
the file has segments at different memory addresses. This means that it
cannot be supplied as a flat binary.
Allow generating a separate node in the FIT for each segment in the ELF,
with a different load address for each.
Also add checks that the fit,xxx directives are valid.
Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>