db845c: Set the flash block size to 4096 am: 2a5ca1a30f am: b2be74f5cd am: 21020703c2

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/2164963

Change-Id: I969180d8ef066b4abf0d7d5ab0150bb56948c1f8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>