Add janitors to the OWNERS file

Test: TreeHugger
Change-Id: I1b834d84602cb0ad94458ab97d2ea02c5862f888
diff --git a/OWNERS b/OWNERS
index 54d8653..06bf9ce 100644
--- a/OWNERS
+++ b/OWNERS
@@ -1,2 +1,3 @@
 include kernel/build:/OWNERS
 
+include platform/system/core:/janitors/OWNERS #{LAST_RESORT_SUGGESTION}