MAINTAINERS: Add maintainers for CTU CAN FD IP core driver

This patch adds an entry for the CTU CAN FD IP to the maintainers
file.

Link: https://lore.kernel.org/all/2cc77e2999d9688bed155e4c7f7807e46d1bf9e3.1647904780.git.pisa@cmp.felk.cvut.cz


Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>