Move the debug message "restarted" and the CAN restart stats_after_
the successful restart of the CAN device, because the restart may
fail.

While there update the error message from printing the error number to
printing symbolic error names.

Link: https://lore.kernel.org/all/20231005-can-dev-fix-can-restart-v2-4-91b5c1fd922c@pengutronix.deReviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
[mkl: mention stats in subject and description, too]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>