can: etas_es58x: Fix missing null check on netdev pointer

There is an assignment to *netdev that is that can potentially be null
but the null check is checking netdev and not *netdev as intended. Fix
this by adding in the missing * operator.

Fixes: 85372578 ("can: etas_es58x: add core support for ETAS ES58X CAN USB interfaces")
Link: https://lore.kernel.org/r/20210415084723.1807935-1-colin.king@canonical.com


Addresses-Coverity: ("Dereference before null check")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>