Update documentation on binderservicedomain

The binderservicedomain attribute grants further permissions than its
name suggests. Update the documentation to avoid its usage.

Bug: 297785784
Test: build, documentation update only.
Change-Id: I41bc6f32cf4d56bde320261fe221c3653cda945a
diff --git a/private/binderservicedomain.te b/private/binderservicedomain.te
index fa9dd7d..21349df 100644
--- a/private/binderservicedomain.te
+++ b/private/binderservicedomain.te
@@ -1,4 +1,5 @@
-# Rules common to all binder service domains
+# Rules common to some specific binder service domains.
+# Deprecated. Consider granting the exact permissions required by your service.
 
 # Allow dumpstate and incidentd to collect information from binder services
 allow binderservicedomain { dumpstate incidentd }:fd use;