Add rand_chacha/OWNERS

Test: make
Change-Id: I37abc405aee8a7765c3e6934ff2e2a2f4fca1c81
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..46fc303
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1 @@
+include platform/prebuilts/rust:/OWNERS