Do keep wait for 10 us after tb_end, otherwise use severity failure to stop...

Do keep wait for 10 us after tb_end, otherwise use severity failure to stop the simulation and avoid the PLL lost lock messages after the tb_end.

libraries/io/eth/tb/vhdl/tb_eth.vhd

@@ -566,7 +566,8 @@ BEGIN
       REPORT "Not all transmitted packets were received." SEVERITY ERROR;
     END IF;
     
-    --WAIT FOR 10 us;
+    -- Do keep wait for 10 us after tb_end. Otherwise without wait for 10 us use severity FAILURE to stop the simulation and avoid the PLL lost lock messages after the tb_end.
+    WAIT FOR 10 us;
     ASSERT FALSE REPORT "Simulation tb_eth finished." SEVERITY NOTE;
     WAIT;
   END PROCESS;