Add OWNERS in device/google/contexthub

* Owners are selected from top CL approvals or owners.
  They will be suggested to review/approve future CLs.
* OWNERS files are recognized by the new find-owners plugin, see .md files in
  https://gerrit.googlesource.com/plugins/find-owners/+/master/src/main/resources/Documentation/

Test: build/make/tools/checkowners.py -c -v OWNERS
Change-Id: Icb48ecc4d31fae8807dd37e66379abbec452490a
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..ede3a5c
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1,2 @@
+dimitrysh@google.com
+fennema@google.com