can: c_can: ethtool: use default drvinfo

The ethtool core implements a default drvinfo.

There's no need to replicate this in the driver, no additional
information is added, so remove this and rely on the default.

Link: https://lore.kernel.org/all/20220124215642.3474154-10-mkl@pengutronix.de


Cc: Dario Binacchi <dariobin@libero.it>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>