Merge "dragonboards: Add boot image header v4 support and remove v2" am: 0258a8aa47 am: df69a58b14 am: 79909d4c71

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/2103029

Change-Id: Id93c2be9dbc1b7df40951edd16364b3ddb50654a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>