convert to zalloc

src/net/netdevice.c

 	size_t total_len;
 
 	total_len = ( sizeof ( *netdev ) + priv_size );
-	netdev = malloc ( total_len );
+	netdev = zalloc ( total_len );
 	if ( netdev ) {
-		memset ( netdev, 0, total_len );
 		netdev->refcnt.free = free_netdev;
 		INIT_LIST_HEAD ( &netdev->tx_queue );
 		INIT_LIST_HEAD ( &netdev->rx_queue );