vty: allow A5/4 encryption in config

Add A5/4 to the internal mask of allowed algorithms.

(Not actually working yet, A5/4 implementation follows in other
patches.)

Related: SYS#5324
Change-Id: I5b46aaa8579f8d069ca39caf996a8795ffe63dd7
diff --git a/tests/test_nodes.vty b/tests/test_nodes.vty
index f956a12..268681a 100644
--- a/tests/test_nodes.vty
+++ b/tests/test_nodes.vty
@@ -16,7 +16,7 @@
   mobile network code <0-999>
   short name NAME
   long name NAME
-  encryption a5 <0-3> [<0-3>] [<0-3>] [<0-3>]
+  encryption a5 <0-4> [<0-4>] [<0-4>] [<0-4>] [<0-4>]
   encryption uea <0-2> [<0-2>] [<0-2>]
   authentication (optional|required)
   rrlp mode (none|ms-based|ms-preferred|ass-preferred)