When accessing the buffer in 1 byte increments, the order should
be reversed for BE.

R=petermarshall@chromium.org, yangguo@chromium.org
BUG=
LOG=N

Change-Id: I27a57e12479d1c00488546a92428b9183d87f8bf
Reviewed-on: https://chromium-review.googlesource.com/667902Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Jaideep Bajwa <bjaideep@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#48031}