[fix] documentation

doc/tutorial/tutorial.tex

@@ -107,7 +107,8 @@ are using, you must run one of the 2 commands:\\
 $> sudo ./st-util /dev/sg2
 
 # STM32L discovery kit
-$> sudo ./st-util
+# 2 dummy command line arguments needed, will be fixed soon
+$> sudo ./st-util fu bar
 \end{lstlisting}
 \end{small}