remove nnk from OWNERS

See https://android-review.googlesource.com/c/platform/system/sepolicy/+/626014

Test: none
Change-Id: Id9c5595cb02d1ec134a93559f25b523ab070ee27
diff --git a/OWNERS b/OWNERS
index f263654..22fee56 100644
--- a/OWNERS
+++ b/OWNERS
@@ -1,3 +1,2 @@
 dcashman@google.com
 jeffv@google.com
-nnk@google.com