code refactoring for Vivado compatibility

hw/rtl/libs/VX_bits_remove.sv

@@ -0,0 +1,21 @@
+`include "VX_platform.vh"
+
+module VX_bits_remove #(
+    parameter N   = 1,
+    parameter S   = 1,
+    parameter POS = 0
+) (
+    input wire [N-1:0] data_in, 
+    output wire [N-S-1:0] data_out
+);
+    `UNUSED_VAR (data_in)
+
+    if (POS == 0) begin
+        assign data_out = data_in[N-1:S];
+    end else if (POS == N) begin
+        assign data_out = data_in[N-S-1:0];
+    end else begin
+        assign data_out = {data_in[N-1:(POS+S)], data_in[POS-1:0]};
+    end    
+
+endmodule