Add enterprise team as owners of all of enrollment/

I think we have enough local knowledge on the Chrome OS Enterprise
team to be owners of the enrollment code - this will also speed up
the review process by allowing us to cycle reviews locally.

Bug: none
Change-Id: I9986d0d7cd38c8c5c5ed0b6d8badbbbccf9e0c83
Reviewed-on: https://chromium-review.googlesource.com/878333Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Commit-Queue: Drew Wilson <atwilson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532005}

chrome/browser/chromeos/login/enrollment/OWNERS

-per-file auto_enrollment_controller.*=atwilson@chromium.org
-per-file auto_enrollment_controller.*=bartfab@chromium.org
-per-file auto_enrollment_controller.*=emaxx@chromium.org
-per-file auto_enrollment_controller.*=tnagel@chromium.org
+atwilson@chromium.org
+bartfab@chromium.org
+emaxx@chromium.org
+tnagel@chromium.org