patman: add Commit-notes tag and section

Sometimes a commit should have notes enclosed with it rather
than withing the cover letter -- possibly even because there
is no cover letter. Add a 'Commit-notes' tag, similar to the
'Series-notes' one; lines between this tag and the next END
line are inserted in the patch right after the '---' commit
delimiter.

Change-Id: I01e99ae125607dc6dec08f3be8a5a0b37f0a483d
Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
Signed-off-by: Simon Glass <sjg@chromium.org>
(Updated README)

tools/patman/commit.py

@@ -21,6 +21,7 @@ class Commit:
         changes: Dict containing a list of changes (single line strings).
             The dict is indexed by change version (an integer)
         cc_list: List of people to aliases/emails to cc on this commit
+        notes: List of lines in the commit (not series) notes
     """
     def __init__(self, hash):
         self.hash = hash
@@ -28,6 +29,7 @@ class Commit:
         self.tags = []
         self.changes = {}
         self.cc_list = []
+        self.notes = []
 
     def AddChange(self, version, info):
         """Add a new change line to the change list for a version.