Bluetooth: Always allow SCO packets for user channel

The SCO packets from Bluetooth raw socket are now rejected because
hci_conn_num is left 0. This patch allows such the usecase to enable
the userspace SCO support.

Fixes: b16b327 ("Bluetooth: btusb: add sysfs attribute to control USB alt setting")
Signed-off-by: Hsin-chen Chuang <chharry@chromium.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Author: Hsin-chen Chuang

drivers/bluetooth/btusb.c

@@ -2102,7 +2102,8 @@ static int btusb_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
 		return submit_or_queue_tx_urb(hdev, urb);
 
 	case HCI_SCODATA_PKT:
-		if (hci_conn_num(hdev, SCO_LINK) < 1)
+		if (!hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
+		    hci_conn_num(hdev, SCO_LINK) < 1)
 			return -ENODEV;
 
 		urb = alloc_isoc_urb(hdev, skb);
@@ -2576,7 +2577,8 @@ static int btusb_send_frame_intel(struct hci_dev *hdev, struct sk_buff *skb)
 		return submit_or_queue_tx_urb(hdev, urb);
 
 	case HCI_SCODATA_PKT:
-		if (hci_conn_num(hdev, SCO_LINK) < 1)
+		if (!hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
+		    hci_conn_num(hdev, SCO_LINK) < 1)
 			return -ENODEV;
 
 		urb = alloc_isoc_urb(hdev, skb);