added xon backpressure to flush tx stream when pause frames are received

by MAC

Closes L2SDP-759

applications/lofar2/libraries/sdp/src/vhdl/sdp_station.vhd

@@ -1045,13 +1045,14 @@ BEGIN
     ---------------
     u_nw_10GbE_beamlet_output: ENTITY nw_10GbE_lib.nw_10GbE
     GENERIC MAP (
-      g_sim           => g_sim,
-      g_sim_level     => 1,
-      g_nof_macs      => c_nof_10GbE_beamlet_output,
-      g_direction     => "TX_RX",
-      g_tx_fifo_fill  => c_fifo_tx_fill_beamlet_output,
-      g_tx_fifo_size  => c_fifo_tx_size_beamlet_output,
-      g_ip_hdr_field_arr => c_sdp_cep_hdr_field_arr
+      g_sim              => g_sim,
+      g_sim_level        => 1,
+      g_nof_macs         => c_nof_10GbE_beamlet_output,
+      g_direction        => "TX_RX",
+      g_tx_fifo_fill     => c_fifo_tx_fill_beamlet_output,
+      g_tx_fifo_size     => c_fifo_tx_size_beamlet_output,
+      g_ip_hdr_field_arr => c_sdp_cep_hdr_field_arr,
+      g_xon_backpressure => TRUE
   
     )
     PORT MAP (