mailmap: update email address of Matthias Fuchs and Thomas Körper

Matthias Fuchs's and Thomas Körper's email addresses aren't valid
anymore. Use the newly created role account instead.

Link: https://lore.kernel.org/r/20210809175843.207864-1-mkl@pengutronix.de


Cc: socketcan@esd.eu
Cc: Stefan Mätje <Stefan.Maetje@esd.eu>
Acked-by: Stefan Mätje <stefan.maetje@esd.eu>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>