[Autofill] Change ownership of autofill_scaled_resources

Reflects current team structure.

BUG=None
TBR=blundell

Review-Url: https://codereview.chromium.org/2888573002
Cr-Commit-Position: refs/heads/master@{#472253}

components/resources/OWNERS

-per-file autofill_scaled_resources.grdp=estade@chromium.org
+per-file autofill_scaled_resources.grdp=mathp@chromium.org
 per-file content_suggestions*=file://components/ntp_snippets/OWNERS
 per-file crash_*=cpu@chromium.org
 per-file crash_*=jochen@chromium.org