net: dev_ioctl: remove redundant initialization of variable err

The variable err is being initialized with a value that is never read
and it is being updated later with a new value.  The initialization is
redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20201102121615.695196-1-colin.king@canonical.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

net/core/dev_ioctl.c

@@ -230,7 +230,7 @@ static int dev_do_ioctl(struct net_device *dev,
 			struct ifreq *ifr, unsigned int cmd)
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
-	int err = -EOPNOTSUPP;
+	int err;
 
 	err = dsa_ndo_do_ioctl(dev, ifr, cmd);
 	if (err == 0 || err != -EOPNOTSUPP)