devices: af_packet, fix tx stall by retrying failed sendto

Change-Id: I6bed66f740b34673a4883eda1c7f7310c57e131b
Type: fix
Signed-off-by: Mohammed Hawari <mohammed@hawari.fr>
Signed-off-by: Benoît Ganne <bganne@cisco.com>
diff --git a/src/vnet/devices/af_packet/af_packet.h b/src/vnet/devices/af_packet/af_packet.h
index 10a7aaf..e5dc615 100644
--- a/src/vnet/devices/af_packet/af_packet.h
+++ b/src/vnet/devices/af_packet/af_packet.h
@@ -82,6 +82,7 @@
   u32 rx_frame_offset;
   u16 num_rx_pkts;
   u8 is_rx_pending;
+  u8 is_tx_pending;
   vnet_hw_if_rx_mode mode;
 } af_packet_queue_t;