can: c_can: c_can_do_tx(): fix typo in comment

This patch fixes a typo in the comment in c_can_do_tx().

Fixes: eddf6711 ("can: c_can: add a comment about IF_RX interface's use")
Link: https://lore.kernel.org/r/20210806105127.103302-1-mkl@pengutronix.de


Cc: Dario Binacchi <dariobin@libero.it>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>