scripts: twister: help - change help text to match hwmv2

fix the twister help text, boards are now organized as:
boards/<vendor>/<board_name>

Signed-off-by: Lothar Felten <[email protected]>

Author: lfelten

scripts/pylib/twister/twisterlib/environment.py

@@ -257,7 +257,7 @@ def add_parse_arguments(parser = None):
         "-A", "--board-root", action="append", default=board_root_list,
         help="""Directory to search for board configuration files. All .yaml
 files in the directory will be processed. The directory should have the same
-structure in the main Zephyr tree: boards/<arch>/<board_name>/""")
+structure in the main Zephyr tree: boards/<vendor>/<board_name>/""")
 
     parser.add_argument(
         "--allow-installed-plugin", action="store_true", default=None,