u_boot_pylib: Provide directories to gitutil functions

For testing it is useful to be able to set the current directory used
for git operations, as well as the git-repo directory. Update some of
the functions to support this.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/u_boot_pylib/command.py b/tools/u_boot_pylib/command.py
index 0e24735..cb7ebf4 100644
--- a/tools/u_boot_pylib/command.py
+++ b/tools/u_boot_pylib/command.py
@@ -203,7 +203,7 @@
     return run_pipe([cmd], **kwargs)
 
 
-def run_list(cmd):
+def run_list(cmd, **kwargs):
     """Run a command and return its output
 
     Args:
@@ -211,8 +211,9 @@
 
     Returns:
         str: output of command
+        **kwargs (dict of args): Extra arguments to pass in
     """
-    return run_pipe([cmd], capture=True).stdout
+    return run_pipe([cmd], capture=True, **kwargs).stdout
 
 
 def stop_all():