ctrl/vty: fsm: use correct element when iterating over fsm->proc.children

Fixes crashes when using vty `show fsm-instances all`
when fsm children are present.

Change-Id: I4ae0bee7f7f57ec6675cfb52ca6cf0d523d15362
diff --git a/src/ctrl/fsm_ctrl_commands.c b/src/ctrl/fsm_ctrl_commands.c
index 3c7e1bd..c93d3a5 100644
--- a/src/ctrl/fsm_ctrl_commands.c
+++ b/src/ctrl/fsm_ctrl_commands.c
@@ -156,7 +156,7 @@
 	if (fi->proc.parent)
 		cmd->reply = talloc_asprintf_append(cmd->reply, ",parent='%s'", fi->proc.parent->name);
 
-	llist_for_each_entry(child, &fi->proc.children, list) {
+	llist_for_each_entry(child, &fi->proc.children, proc.child) {
 		cmd->reply = talloc_asprintf_append(cmd->reply, ",child='%s'", child->name);
 	}