OmniControl: move to system_ext

Change-Id: If10d980de91f7a6cef6cbfa20110951d53a7fca7
diff --git a/Android.bp b/Android.bp
index 8ea60ce..405998a 100644
--- a/Android.bp
+++ b/Android.bp
@@ -4,6 +4,7 @@
   platform_apis: true,
   certificate: "platform",
   privileged: true,
+  system_ext_specific: true,
 
   srcs: [
     "app/src/main/**/*.kt",