code refactoring for Vivado compatibility

hw/rtl/interfaces/VX_join_if.sv

@@ -0,0 +1,23 @@
+`ifndef VX_JOIN_IF
+`define VX_JOIN_IF
+
+`include "VX_define.vh"
+
+interface VX_join_if ();
+
+    wire                valid;
+    wire [`NW_BITS-1:0] wid;
+
+    modport master (
+        output valid,    
+        output wid
+    );
+
+    modport slave (
+        input valid,   
+        input wid
+    );
+
+endinterface
+
+`endif