tools: Plumb in capture control

Add control of capturing output into u_boot_pylib and the tools which
use it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/u_boot_pylib/__main__.py b/tools/u_boot_pylib/__main__.py
index c0762bc..d86b9d7 100755
--- a/tools/u_boot_pylib/__main__.py
+++ b/tools/u_boot_pylib/__main__.py
@@ -16,7 +16,7 @@
     from u_boot_pylib import test_util
 
     result = test_util.run_test_suites(
-        'u_boot_pylib', False, False, False, None, None, None,
+        'u_boot_pylib', False, False, False, False, None, None, None,
         ['terminal'])
 
     sys.exit(0 if result.wasSuccessful() else 1)