util: postprocess: remove support for elf, restructure relocation code

Change-Id: Ie6b4b52c3e26ca6abc2d5067b5f97290c50f7105
Signed-off-by: Alexey Polyudov <apolyudov@google.com>
(cherry picked from commit d489d84b219a2b635d30bd4314f6698fbffe98a8)
3 files changed