can: c_can: don't cache TX messages for C_CAN cores

commit 81d192c2 upstream.

As Jacob noticed, the optimization introduced in 387da6bc ("can:
c_can: cache frames to operate as a true FIFO") doesn't properly work
on C_CAN, but on D_CAN IP cores. The exact reasons are still unknown.

For now disable caching if CAN frames in the TX path for C_CAN cores.

Fixes: 387da6bc ("can: c_can: cache frames to operate as a true FIFO")
Link: https://lore.kernel.org/all/20220928083354.1062321-1-mkl@pengutronix.de
Link: https://lore.kernel.org/all/15a8084b-9617-2da1-6704-d7e39d60643b@gmail.com


Reported-by: Jacob Kroon <jacob.kroon@gmail.com>
Tested-by: Jacob Kroon <jacob.kroon@gmail.com>
Cc: stable@vger.kernel.org # v5.15
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>