Add instruction `qemu_clean` before rebuilding

Change-Id: Ie0b43c99f461c7fa0b0464a3547b50d1626e156e

Create_Springbok_Vector_Unit_Test.md

diff --git a/Create_Springbok_Vector_Unit_Test.md b/Create_Springbok_Vector_Unit_Test.md
index 6973ba8..afc9aa5 100644
--- a/Create_Springbok_Vector_Unit_Test.md
+++ b/Create_Springbok_Vector_Unit_Test.md
@@ -16,7 +16,7 @@
 ```sh
 repo sync
 m renode_clean renode
-m qemu
+m qemu_clean qemu
 ```
 ## Step 1: Select Instruction and Update Tracker