cbfstool: Use cbfs_image API for "add-*" (add-payload, add-stage, ...) commands.

add-payload, add-stage, and add-flat-binary are now all using cbfs_image API.
To test:
	cbfstool coreboot.rom add-stage -f FILE -n fallback/romstage -b 0xXXXX
	cbfstool coreboot.rom add-payload -f FILE -n fallback/pyload
And compare with old cbfstool.

Verified to boot on ARM(snow) and X86(qemu-i386).

Change-Id: If65cb495c476ef6f9d90c778531f0c3caf178281
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: http://review.coreboot.org/2220
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
4 files changed