scripts: Undo Board.{dir -> directories[0]} renames

`Board.dir` can be used in place of `Board.directories[0]` for brevity.

Signed-off-by: Grzegorz Swiderski <grzegorz.swiderski@nordicsemi.no>
diff --git a/scripts/list_boards.py b/scripts/list_boards.py
index 44247b4..443e18a 100755
--- a/scripts/list_boards.py
+++ b/scripts/list_boards.py
@@ -447,7 +447,7 @@
             if args.cmakeformat is not None:
                 info = args.cmakeformat.format(
                     NAME='NAME;' + board.name,
-                    DIR='DIR;' + str(board.directories.as_posix()),
+                    DIR='DIR;' + str(board.dir.as_posix()),
                     HWM='HWM;' + board.hwm,
                     VENDOR='VENDOR;NOTFOUND',
                     REVISION_DEFAULT='REVISION_DEFAULT;NOTFOUND',