can: m_can: m_can_handle_lost_msg(): downgrade msg lost in rx message to debug level

Downgrade the "msg lost in rx" message to debug level, to prevent
flooding the kernel log with error messages.

Fixes: e0d1f481 ("can: m_can: add Bosch M_CAN controller support")
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Link: https://patch.msgid.link/20250711-mcan_ratelimit-v3-1-7413e8e21b84@geanix.com


[mkl: enhance commit message]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>