net: ieee802154: remove an unnecessary null pointer check

llsec_parse_seclevel has the null pointer check at its begining. Compared
with nl802154_add_llsec_seclevel, nl802154_del_llsec_seclevel has a
redundant null pointer check of info->attrs[NL802154_ATTR_SEC_LEVEL]
before llsec_parse_seclevel.

Fix this issue by removing the null pointer check in
nl802154_del_llsec_seclevel.

Signed-off-by: Dongliang Mu <dzm91@hust.edu.cn>
Link: https://lore.kernel.org/r/20230308083231.460015-1-dzm91@hust.edu.cn
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>

Author: mudongliang

net/ieee802154/nl802154.c

@@ -2488,8 +2488,7 @@ static int nl802154_del_llsec_seclevel(struct sk_buff *skb,
 	if (wpan_dev->iftype == NL802154_IFTYPE_MONITOR)
 		return -EOPNOTSUPP;
 
-	if (!info->attrs[NL802154_ATTR_SEC_LEVEL] ||
-	    llsec_parse_seclevel(info->attrs[NL802154_ATTR_SEC_LEVEL],
+	if (llsec_parse_seclevel(info->attrs[NL802154_ATTR_SEC_LEVEL],
 				 &sl) < 0)
 		return -EINVAL;