fpga: n3xx: Fix White Rabbit images

Unused CHDR port was not being drained of discovery packets.


Original-commit: 8d57586d61356c42a80408b6bd71e8f74a8d40e2

top/n3xx/n3xx_mgt_wrapper.v

@@ -328,9 +328,8 @@ module n3xx_mgt_wrapper #(
 
   generate
     // Tie off the Ethernet switch for these protocols that do not use it.
-    if(PROTOCOL == "Aurora" || PROTOCOL == "Disabled" || PROTOCOL == "WhiteRabbit") begin
-
-      //set unused wires to default value
+    if(PROTOCOL == "Aurora" || PROTOCOL == "Disabled") begin
+      // Set unused wires to default values
       assign e2c_tdata      = 64'h0;
       assign e2c_tkeep      = 8'h0;
       assign e2c_tlast      = 1'b0;
@@ -350,6 +349,23 @@ module n3xx_mgt_wrapper #(
       assign mgti_tvalid    = v2e_tvalid;
       assign v2e_tready     = mgti_tready;
 
+    end else if(PROTOCOL == "WhiteRabbit") begin
+      // Set unused wires to default values
+      assign e2c_tdata      = 64'h0;
+      assign e2c_tkeep      = 8'h0;
+      assign e2c_tlast      = 1'b0;
+      assign e2c_tvalid     = 1'b0;
+      assign c2e_tready     = 1'b1;
+
+      assign reg_rd_resp_eth_if = 1'b0;
+      assign reg_rd_data_eth_if = 'h0;
+
+      assign e2v_tdata      = 64'b0;
+      assign e2v_tlast      =  1'b0;
+      assign e2v_tvalid     =  1'b0;
+
+      assign v2e_tready     = 1'b1;
+
     end else begin
 
       wire [3:0] e2c_tuser;