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

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

Change-Id: I5a39d2dbff68d91c50293d5a01b3d0fde915a3c2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>