openflow_input: use padding member syntax
diff --git a/openflow_input/bsn_get_interfaces b/openflow_input/bsn_get_interfaces
index f170d6f..d2105a2 100644
--- a/openflow_input/bsn_get_interfaces
+++ b/openflow_input/bsn_get_interfaces
@@ -38,7 +38,7 @@
 
 struct of_bsn_interface {
     of_mac_addr_t hw_addr;
-    uint16_t pad;
+    pad(2);
     of_port_name_t name;
     uint32_t ipv4_addr;
     uint32_t ipv4_netmask;