Bluetooth: Fix memory leak in hci_req_sync_complete()

In 'hci_req_sync_complete()', always free the previous sync
request state before assigning reference to a new one.

Reported-by: syzbot+39ec16ff6cc18b1d066d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=39ec16ff6cc18b1d066d
Cc: stable@vger.kernel.org
Fixes: f60cb305 ("Bluetooth: Convert hci_req_sync family of function to new request API")
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

net/bluetooth/hci_request.c

@@ -105,8 +105,10 @@ void hci_req_sync_complete(struct hci_dev *hdev, u8 result, u16 opcode,
 	if (hdev->req_status == HCI_REQ_PEND) {
 		hdev->req_result = result;
 		hdev->req_status = HCI_REQ_DONE;
-		if (skb)
+		if (skb) {
+			kfree_skb(hdev->req_skb);
 			hdev->req_skb = skb_get(skb);
+		}
 		wake_up_interruptible(&hdev->req_wait_q);
 	}
 }