Packet fenerator fix and inter-packet delay reimplemented

Changes in the inter-packet delay counter (still unclear whether fully fixed uneven occupancy of the buffer) and fixed the packet generator, which fixed issue with overfilling of the buffer

mars-vhdl/hdl/axi_join.vhd

@@ -150,7 +150,7 @@ begin
    ipw_cnt_done_proc : process(clk)
    begin
       if rising_edge(clk) then
-         if ipw_cnt >= unsigned((ipw_delay & X"0") then   --if counter reached certain level
+         if ipw_cnt >= unsigned(ipw_delay & X"0") then   --if counter reached certain level
             ipw_cnt_done <= '1';        --consider counting done
          else
             ipw_cnt_done <= '0';        --otherwise wait is needed