can: ctucanfd: ctucan_interrupt(): fix typo

This patch fixes the typo "poniter" -> "pointer" in the kerneldoc of
ctucan_interrupt().

Link: https://lore.kernel.org/all/20220628083204.881311-1-mkl@pengutronix.de
Fixes: 2dcb8e87

 ("can: ctucanfd: add support for CTU CAN FD open-source IP core - bus independent part.")
Cc: Ondrej Ille <ondrej.ille@gmail.com>
Cc: Martin Jerabek <martin.jerabek01@gmail.com>
Acked-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>