tdef_vty.h: Add missing header dependencies

enum node_type is defined in osmocom/vty/command.h
va_list is defined in stdarg.h

Change-Id: Ia439a7097ae7a9765e229e5f66e07af3fe490ecc
diff --git a/include/osmocom/vty/tdef_vty.h b/include/osmocom/vty/tdef_vty.h
index 3027913..6334d5b 100644
--- a/include/osmocom/vty/tdef_vty.h
+++ b/include/osmocom/vty/tdef_vty.h
@@ -25,6 +25,9 @@
 #pragma once
 
 #include <stdint.h>
+#include <stdarg.h>
+
+#include <osmocom/vty/command.h>
 
 struct vty;