futility: refactor to handle each file type individually

Instead of calling futil_traverse() to iterate through a preset
list of functions, this establishes a separate show() and sign()
function for each type of file.

The only significant change is that walking through the FMAP areas
within BIOS images is done in BIOS-specific functions instead of
that being the "normal" case with every other type of file
skipping that traversal.

This is a refactoring only. There is no externally visible change.

BUG=chromium:231574
BRANCH=none
TEST=make runtests

Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Change-Id: I7080afb43e35308c8bb618793c8382c2efb3d6a1
Reviewed-on: https://chromium-review.googlesource.com/262894
Reviewed-by: Randall Spangler <rspangler@chromium.org>
8 files changed