[fido] Add kpaulhamus and hongjunchoi as OWNERs

This change adds kpaulhamus@ and hongjunchoi@ as OWNERs for
//device/fido. Both of them have numerous contributions to this folder
and are very familiar with the codebase. Furthermore, both of them
have obtained the required committer status.

Bug: NONE
Change-Id: Idfa3343e865f862288a214e06f0b065f205b6546
Reviewed-on: https://chromium-review.googlesource.com/1116921Reviewed-by: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Balazs Engedy <engedy@chromium.org>
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570819}

device/fido/OWNERS

 reillyg@chromium.org
 jdoerrie@chromium.org
 engedy@chromium.org
+kpaulhamus@chromium.org
+hongjunchoi@chromium.org
 
 # TEAM: security-dev@chromium.org
 # COMPONENT: Blink>WebAuthentication