Add a TODO to remove mlsvendorcompat.

One day we won't need this mechanism any more & can remove all traces
of it.

Bug: 141677108
Test: builds
Change-Id: I95525a163ab4f19d8ca411c02a3c06498c6777ef
diff --git a/private/compat/30.0/30.0.compat.cil b/private/compat/30.0/30.0.compat.cil
index f262bbd..97c5874 100644
--- a/private/compat/30.0/30.0.compat.cil
+++ b/private/compat/30.0/30.0.compat.cil
@@ -1,6 +1,8 @@
 (typeattribute vendordomain)
 (typeattributeset vendordomain ((and (domain) ((not (coredomain))))))
 
+;; TODO: Once 30.0 is no longer supported for vendor images,
+;; mlsvendorcompat can be completely from the system policy.
 (typeattributeset mlsvendorcompat (and appdomain vendordomain))
 (allow mlsvendorcompat app_data_file (dir (ioctl read write create getattr setattr lock rename open watch watch_reads add_name remove_name reparent search rmdir)))
 (allow mlsvendorcompat app_data_file (file (ioctl read write create getattr setattr lock append map unlink rename open watch watch_reads)))