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/binman/ftest.py b/tools/binman/ftest.py
index d3e6e67..ffef213 100644
--- a/tools/binman/ftest.py
+++ b/tools/binman/ftest.py
@@ -274,7 +274,7 @@
 
     @classmethod
     def setup_test_args(cls, preserve_indir=False, preserve_outdirs=False,
-                        toolpath=None, verbosity=None):
+                        toolpath=None, verbosity=None, no_capture=False):
         """Accept arguments controlling test execution
 
         Args:
@@ -289,6 +289,7 @@
         cls.preserve_outdirs = preserve_outdirs
         cls.toolpath = toolpath
         cls.verbosity = verbosity
+        cls.no_capture = no_capture
 
     def _CheckBintool(self, bintool):
         if not bintool.is_present():