Bluetooth: btintel: Fix null ptr deref in btintel_read_version

If hci_cmd_sync_complete() is triggered and skb is NULL, then
hdev->req_skb is NULL, which will cause this issue.

Reported-and-tested-by: syzbot+830d9e3fa61968246abd@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

drivers/bluetooth/btintel.c

@@ -435,7 +435,7 @@ int btintel_read_version(struct hci_dev *hdev, struct intel_version *ver)
 	struct sk_buff *skb;
 
 	skb = __hci_cmd_sync(hdev, 0xfc05, 0, NULL, HCI_CMD_TIMEOUT);
-	if (IS_ERR(skb)) {
+	if (IS_ERR_OR_NULL(skb)) {
 		bt_dev_err(hdev, "Reading Intel version information failed (%ld)",
 			   PTR_ERR(skb));
 		return PTR_ERR(skb);