openflow_input: use padding member syntax
diff --git a/openflow_input/bsn_table_mod b/openflow_input/bsn_table_mod
index 6161abf..fe2dd73 100644
--- a/openflow_input/bsn_table_mod
+++ b/openflow_input/bsn_table_mod
@@ -35,6 +35,6 @@
     uint16_t length;
     uint32_t xid;
     uint8_t table_id;
-    uint8_t[3] pad;
+    pad(3);
     uint32_t config;
 };