buildman: Drop use of 'boards' in control

Use brds instead so that we can reserve 'boards' for a module name.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/buildman/func_test.py b/tools/buildman/func_test.py
index 812dc92..23627f3 100644
--- a/tools/buildman/func_test.py
+++ b/tools/buildman/func_test.py
@@ -239,7 +239,7 @@
         sys.argv = [sys.argv[0]] + list(args)
         options, args = cmdline.ParseArgs()
         result = control.DoBuildman(options, args, toolchains=self._toolchains,
-                make_func=self._HandleMake, boards=brds or self._boards,
+                make_func=self._HandleMake, brds=brds or self._boards,
                 clean_dir=clean_dir,
                 test_thread_exceptions=test_thread_exceptions)
         self._builder = control.builder