patman: Convert camel case in cros_subprocess.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/command.py b/tools/patman/command.py
index c848aa1..2435878 100644
--- a/tools/patman/command.py
+++ b/tools/patman/command.py
@@ -108,7 +108,7 @@
 
     if capture:
         result.stdout, result.stderr, result.combined = (
-                last_pipe.CommunicateFilter(output_func))
+                last_pipe.communicate_filter(output_func))
         if result.stdout and oneline:
             result.output = result.stdout.rstrip(b'\r\n')
         result.return_code = last_pipe.wait()