ng_atmllc: deprecate

With the deprecation of NgATM, ng_atmllc is the last vestage of ATM
support so deprecate it too.

MFC after:	3 days
Relnotes:	yes

Reviewed by:	manu, emaste
Differential Revision:	https://reviews.freebsd.org/D38878

share/man/man4/ng_atmllc.4

@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 8, 2004
+.Dd March 3, 2023
 .Dt NG_ATMLLC 4
 .Os
 .Sh NAME
@@ -32,6 +32,11 @@
 .Nd ATM LLC netgraph node type
 .Sh SYNOPSIS
 .In netgraph/ng_atmllc.h
+.Sh DEPRECATION NOTICE
+.Nm
+is deprecated and may not be available in
+.Fx 14.0
+and later.
 .Sh DESCRIPTION
 The
 .Nm atmllc

sys/netgraph/ng_atmllc.c

@@ -93,6 +93,8 @@ ng_atmllc_constructor(node_p node)
 {
 	struct	ng_atmllc_priv *priv;
 
+	gone_in(14, "ng_atmllc");
+
 	priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
 	NG_NODE_SET_PRIVATE(node, priv);