Add OWNERS in system/hwservicemanager

* 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: Icbc871cbb5ceb5db5a2f8f0898cf3eb7a02b6900
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..b893bf2
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1,4 @@
+elsk@google.com
+maco@google.com
+malchev@google.com
+smoreland@google.com