patman: Convert camel case in commit.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/series.py b/tools/patman/series.py
index da734d9..98b4c9c 100644
--- a/tools/patman/series.py
+++ b/tools/patman/series.py
@@ -94,7 +94,7 @@
         Args:
             commit: Commit object to add
         """
-        commit.CheckTags()
+        commit.check_tags()
         self.commits.append(commit)
 
     def ShowActions(self, args, cmd, process_tags):