can: mcp251xfd: mcp251xfd_dump(): fix comment

The driver uses only 1 TEF and 1 TX ring, but a variable number of RX
rings. Fix comment accordingly.

Fixes: e0ab3dd5 ("can: mcp251xfd: add dev coredump support")
Link: https://lore.kernel.org/all/20220726084328.4042678-1-mkl@pengutronix.de


Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>