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: NColin Ian King <colin.king@canonical.com>
Acked-by: NVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/usb/etas_es58x/es58x_core.h

@@ -625,7 +625,7 @@ static inline int es58x_get_netdev(struct es58x_device *es58x_dev,
 		return -ECHRNG;
 
 	*netdev = es58x_dev->netdev[channel_idx];
-	if (!netdev || !netif_device_present(*netdev))
+	if (!*netdev || !netif_device_present(*netdev))
 		return -ENODEV;
 
 	return 0;