net: at91_can: fix the comments style issue

Networking block comments don't use an empty /* line,
use /* Comment...

Block comments use * on subsequent lines.
Block comments use a trailing */ on a separate line.

This patch fixes the comments style issues.

Link: https://lore.kernel.org/r/1624096589-13452-9-git-send-email-huangguangbin2@huawei.com


Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>