pack_firmware: Fixes from review feedback.

Fixes from CL:428734.

- change vboot1/vboot2 to fmap/cbfs.
- extract cbfs contents directly without dump_fmap first.
- parse dump_fmap output by bash array and prevent off-hand operations.
- correct EC section size checking: should be '>=' instead of '>'.
- move dd & python into individual python helpers in utils folder.

BUG=chromium:674799
TEST=emerge-asuka chromeos-firmware-asuka
     emerge-kefka chromeos-firmware-kefka
     emerge-lumpy chromoes-firmware-lumpy

Change-Id: I8b7c136384a708535943df0b14fae08e5253d607
Reviewed-on: https://chromium-review.googlesource.com/430464
Commit-Ready: Hung-Te Lin <[email protected]>
Tested-by: Hung-Te Lin <[email protected]>
Reviewed-by: Hung-Te Lin <[email protected]>
(cherry picked from commit 3e730d2d05e0756b9f9eb0890d5b955beef52d66)
Reviewed-on: https://chromium-review.googlesource.com/431003
Reviewed-by: YH Lin <[email protected]>
Commit-Queue: YH Lin <[email protected]>
Tested-by: YH Lin <[email protected]>
3 files changed