nfc: digital: free skb on digital_in_send error paths

digital_in_send() takes ownership of the skb passed by the caller
(nfc_data_exchange), make sure it's freed on all error paths.

Found looking around the real driver for similar bugs to the one
just fixed in nci.

Fixes: 2c66dae ("NFC Digital: Add NFC-A technology support")
Reviewed-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260303162346.2071888-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

net/nfc/digital_core.c

@@ -707,8 +707,10 @@ static int digital_in_send(struct nfc_dev *nfc_dev, struct nfc_target *target,
 	int rc;
 
 	data_exch = kzalloc_obj(*data_exch);
-	if (!data_exch)
+	if (!data_exch) {
+		kfree_skb(skb);
 		return -ENOMEM;
+	}
 
 	data_exch->cb = cb;
 	data_exch->cb_context = cb_context;
@@ -731,8 +733,10 @@ static int digital_in_send(struct nfc_dev *nfc_dev, struct nfc_target *target,
 				 data_exch);
 
 exit:
-	if (rc)
+	if (rc) {
+		kfree_skb(skb);
 		kfree(data_exch);
+	}
 
 	return rc;
 }