doorlock.rst: add BOSSA as a flash tool

Currently, the instructions tell to use west, however there was raised issue that instructions are not clear. For me, flashing with BOSSA worked fine.

Relates to: eclipse/oniro-core/docs#141 (closed)

CC: @fldn

Signed-off-by: Grzegorz Gwozdz grzegorz.gwozdz@huawei.com

doorlock.rst

@@ -266,11 +266,15 @@ Flashing the software when built with west
         $ make bossac
         $ sudo cp bin/bossac /usr/local/bin # (or any other place in your PATH)
 
-#. Use west to flash the software
+#. Use BOSSA to flash the software
 
     .. code-block:: bash
 
-        $ west flash
+        $ bossac -p ttyACM0 -R -e -w -v -b build/zephyr/zephyr.bin
+
+.. note::
+    You may need to replace `ttyACM0`.
+
 
 Resources
 =========
@@ -337,8 +341,12 @@ Flashing the factory reset firmware
         $ make bossac
         $ sudo cp bin/bossac /usr/local/bin # (or any other place in your PATH)
 
-#. Use west to flash the software
+#. Use BOSSA to flash the software
 
     .. code-block:: bash
 
-        $ west flash
+        $ bossac -p ttyACM0 -R -e -w -v -b build/zephyr/zephyr.bin
+
+.. note::
+    You may need to replace `ttyACM0`.
+    
\ No newline at end of file