net/ieee802154: drop unneeded assignment in llsec_iter_devkeys()

In order to keep the code style consistency of the whole file,
redundant return value ‘rc’ and its assignments should be deleted

The clang_analyzer complains as follows:
net/ieee802154/nl-mac.c:1203:12: warning: Although the value stored to
'rc' is used in the enclosing expression, the value is never actually
read from 'rc'

No functional change, only more efficient.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Link: https://lore.kernel.org/r/1619346299-40237-1-git-send-email-yang.lee@linux.alibaba.comSigned-off-by: Stefan Schmidt <stefan@datenfreihafen.org>

net/ieee802154/nl-mac.c

@@ -1184,7 +1184,7 @@ static int llsec_iter_devkeys(struct llsec_dump_data *data)
 {
 	struct ieee802154_llsec_device *dpos;
 	struct ieee802154_llsec_device_key *kpos;
-	int rc = 0, idx = 0, idx2;
+	int idx = 0, idx2;
 
 	list_for_each_entry(dpos, &data->table->devices, list) {
 		if (idx++ < data->s_idx)
@@ -1200,7 +1200,7 @@ static int llsec_iter_devkeys(struct llsec_dump_data *data)
 						      data->nlmsg_seq,
 						      dpos->hwaddr, kpos,
 						      data->dev)) {
-				return rc = -EMSGSIZE;
+				return -EMSGSIZE;
 			}
 
 			data->s_idx2++;
@@ -1209,7 +1209,7 @@ static int llsec_iter_devkeys(struct llsec_dump_data *data)
 		data->s_idx++;
 	}
 
-	return rc;
+	return 0;
 }
 
 int ieee802154_llsec_dump_devkeys(struct sk_buff *skb,