patman: Convert camel case in command.py

Convert this file to snake case and update all files which use it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/patman/checkpatch.py b/tools/patman/checkpatch.py
index 8978df2..4677a7a 100644
--- a/tools/patman/checkpatch.py
+++ b/tools/patman/checkpatch.py
@@ -213,7 +213,7 @@
     args = [chk, '--no-tree']
     if show_types:
         args.append('--show-types')
-    output = command.Output(*args, fname, raise_on_error=False)
+    output = command.output(*args, fname, raise_on_error=False)
 
     return CheckPatchParse(output, verbose)