add .mailmap for proper git-shortlog output

This is the first version of .mailmap created by hand.
Please see "man git-shortlog" for what this commit is trying to do.

Without this file, for example, "git shortlog -n -s" shows as follows:

  2693  Wolfgang Denk     <------
  1002  Stefan Roese      <------
   811  wdenk             <------
   808  Mike Frysinger
   806  Simon Glass
     [snip]
   177  Matthias Fuchs
   154  stroese           <------
   153  Timur Tabi

And then, with this file, it shows as follows:

  3504  Wolfgang Denk     <------
  1156  Stefan Roese      <------
   808  Mike Frysinger
   806  Simon Glass

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Stefan Roese <sr@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Series-version: 2
Series-to: u-boot
Cover-letter:
Add .mailmap file and a tool to maintain it

END
scripts: add mailmapper, a tool to create/update mailmap file

This tool helps to create/update the mailmap file.

It runs 'git shortlog' internally and searches differently spelled author
names which share the same email address. The author name with the most
commits is asuumed to be a canonical real name. If the number of commits
from the cananonical name is equal to or greater than 'MIN_COMMITS' (=50),
the entry for the cananical name will be output. ('MIN_COMMITS' is used
here because we do not want to create a fat mailmap by adding every author
with only a few commits.)

If there exists a mailmap file specified by the mailmap.file configuration
options or '.mailmap' at the toplevel of the repository, it is used as
a base file.

The base file and the newly added entries are merged together and sorted
alphabetically (but the comment block is kept untouched), and then printed
to standard output.

 Usage
 -----

  scripts/mailmapper

prints the mailmapping to standard output.

  scripts/mailmapper > tmp; mv tmp .mailmap

will be useful for updating '.mailmap' file.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Series-changes: 2
  - Fix a typo in comments.
Update .mailmap using scripts/mailmapper

Add more entries to .mailmap for the canonical names with
50 commits or more.

This commit was generated by the following command:

  scripts/mailmapper > tmp; mv tmp .mailmap

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
scripts/mailmapper: add overwrite option