updater_utils.py

The elf header file is different for arm64. Update it so that
the roareadiff feature can be used on 64bit targets.

Change-Id: Ica4424a6ea9d2e599e1a157353aa5f702a5e4bf8
Acked-by: Kosuke Shitaba <kshibata@qti.qualcomm.com>