Inherit some c/b/resources/settings/chromeos owners from parent dir

Steven and Michael are already owners because they are in
//c/b/resources/settings/OWNERS. This just makes it explicit that
they are good reviewers for the chromeos-specific bits too.

Bug: none
Change-Id: I4ae099a3b12a8d1d8dd5e5a4d1ab1e4ccf3d9b6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1728434Reviewed-by: May Lippert <maybelle@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683255}

chrome/browser/resources/settings/chromeos/OWNERS

 maybelle@chromium.org
 jamescook@chromium.org
+michaelpg@chromium.org
+stevenjb@chromium.org
 
 # COMPONENT: OS>Systems>Settings