opal/util/ethtool: add missing headers

and get Open MPI build on OpenBSD 6.0

opal/util/ethtool.c

@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2016 Karol Mroz.  All rights reserved.
+ * Copyright (c) 2016      Karol Mroz.  All rights reserved.
  * Copyright (c) 2016      Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
- * Copyright (c) 2016 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2016      Cisco Systems, Inc.  All rights reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -18,6 +18,12 @@
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
 #ifdef HAVE_NET_IF_H
 #include <net/if.h>
 #endif