Add: archi and comment in top level | Fix: missing var declaration in reg test bench

tb/tb_registers_bank.v

@@ -2,6 +2,7 @@
 `include "tb_tools.vh"
 
 module tb_registers_bank ();
+    integer     i;
     reg         clk;
     reg         reset;
     reg         we;

tb/tb_tools.vh

@@ -42,4 +42,4 @@
 
 `define next_cycle \
     #1 clk = ~clk; \
-    #1 clk = ~clk;
+    #1 clk = ~clk;