Add information for skipped commit options

Add information for skipped commit options

The unsupported Commit-xxx option are silently skipped
and removed as 're_remove=Commit-\w*', this patch adds
warning message in this case to detect misspelled issue
for the 2 supported options:
  Commit-notes:
  Commit-changes:

For example: the final 's' is missing (Commit-note:)

NB: no issue for Series-xxx option as only the supported
    options are accepted (see valid_series in series.py)

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>