Revert of Enable -Wdeprecated-register. (patchset #5 id:80001 of https://codereview.chromium.org/2780623003/ )

Reason for revert:
Broke os="chromeos" build: crbug.com/705812

Original issue's description:
> Enable -Wdeprecated-register.
>
> No behavior change.
>
> BUG=255186
>
> Review-Url: https://codereview.chromium.org/2780623003
> Cr-Commit-Position: refs/heads/master@{#459973}
> Committed: https://chromium.googlesource.com/chromium/src/+/76ad12fee73e4512dbb9c7a79ffb6cec33fae6f2

TBR=dcheng@chromium.org,rouslan@chromium.org,kbr@chromium.org,thakis@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=255186

Review-Url: https://codereview.chromium.org/2778053003
Cr-Commit-Position: refs/heads/master@{#459989}
8 files changed