can/esd_usb: Add an entry to the MAINTAINERS file

As suggested by Marc, I added an entry for ESD CAN/USB Drivers
to the MAINTAINERS file

Link: https://lore.kernel.org/all/20220624190517.2299701-3-frank.jungclaus@esd.eu


Signed-off-by: Frank Jungclaus <frank.jungclaus@esd.eu>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>