mailmap: Update Jagan Teki's name and email address

Used quite different name's and e-mail address, all of
them mapped to standard name and e-mail address.

Cc: Tom Rini <trini@konsulko.com>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jagan Teki <jteki@openedev.com>