add OWNERS for development/sys-img

(cherrypick of 06e7e92e057c51edeaf5f39cf6d40ff961cedc65.)
Change-Id: I525d351d0d6447772b8454e522099c020525d6ca
diff --git a/sys-img/OWNERS b/sys-img/OWNERS
new file mode 100644
index 0000000..4344504
--- /dev/null
+++ b/sys-img/OWNERS
@@ -0,0 +1,2 @@
+bohu@google.com
+huanr@google.com