This commit did:
1. Sync AVB lib with external/avb, head of commit is:
    commit 6d5326a945c2d17d5d0e7718d5cb97663c3b33a2
    Author: Neal Ostrem <nealo@google.com>
    Date:   Tue Apr 24 13:09:45 2018 -0700

        Merge fix/changes required after merge from AOSP ToT.

        Change library name to one used by AT.
        Test: Built successfully and unit tests pass.
        Change-Id: I5e5fc9a6010d96cfecfc6faf0858ba930cba65a0
2. Change product id in ATX to be full zeros to sync with
   external/avb.
3. Fix build errors and implement ops fsl_set_key_version.
4. Move most nxp modified code to lib/avb/fsl/.

Test: build and boot successfully for imx7d_pico and imx8m_phanbell.

Change-Id: I199a035fe8267b10955299a4b745458d40a2e754
Signed-off-by: Luo Ji <ji.luo@nxp.com>