ethtool: linkinfo: remove an unnecessary NULL check

This code generates a Smatch warning:

    net/ethtool/linkinfo.c:143 ethnl_set_linkinfo()
    warn: variable dereferenced before check 'info' (see line 119)

Fortunately, the "info" pointer is never NULL so the check can be
removed.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: hongrongxuan <hongrongxuan@huawei.com>

net/ethtool/linkinfo.c

@@ -140,8 +140,7 @@ int ethnl_set_linkinfo(struct sk_buff *skb, struct genl_info *info)
 
 	ret = __ethtool_get_link_ksettings(dev, &ksettings);
 	if (ret < 0) {
-		if (info)
-			GENL_SET_ERR_MSG(info, "failed to retrieve link settings");
+		GENL_SET_ERR_MSG(info, "failed to retrieve link settings");
 		goto out_ops;
 	}
 	lsettings = &ksettings.base;