Add rkc to chromeos OWNERS.

Adding myself to OWNERS for chromeos so I can unblock folks when needed.

R=alemate@chromium.org, stevenjb@chromium.org

Bug: None
Change-Id: Ibed17c33a099ccf08e99ba8b45f3aa863d786d5a
Reviewed-on: https://chromium-review.googlesource.com/1028612Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Rahul Chaturvedi <rkc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553751}

chrome/browser/chromeos/OWNERS

@@ -7,6 +7,7 @@ alemate@chromium.org
 derat@chromium.org
 jamescook@chromium.org
 oshima@chromium.org
+rkc@chromium.org
 satorux@chromium.org
 stevenjb@chromium.org
 xiyuan@chromium.org

chromeos/OWNERS

@@ -7,6 +7,7 @@ achuith@chromium.org
 alemate@chromium.org
 derat@chromium.org
 oshima@chromium.org
+rkc@chromium.org
 satorux@chromium.org
 stevenjb@chromium.org
 xiyuan@chromium.org