Bluetooth: qca: fix NULL-deref on non-serdev setup

Qualcomm ROME controllers can be registered from the Bluetooth line
discipline and in this case the HCI UART serdev pointer is NULL.

Add the missing sanity check to prevent a NULL-pointer dereference when
setup() is called for a non-serdev controller.

Fixes: e9b3e5b ("Bluetooth: hci_qca: only assign wakeup with serial port support")
Cc: [email protected]      # 6.2
Cc: Zhengping Jiang <[email protected]>
Signed-off-by: Johan Hovold <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>

Author: jhovold

drivers/bluetooth/hci_qca.c

@@ -1958,8 +1958,10 @@ static int qca_setup(struct hci_uart *hu)
 		qca_debugfs_init(hdev);
 		hu->hdev->hw_error = qca_hw_error;
 		hu->hdev->cmd_timeout = qca_cmd_timeout;
-		if (device_can_wakeup(hu->serdev->ctrl->dev.parent))
-			hu->hdev->wakeup = qca_wakeup;
+		if (hu->serdev) {
+			if (device_can_wakeup(hu->serdev->ctrl->dev.parent))
+				hu->hdev->wakeup = qca_wakeup;
+		}
 	} else if (ret == -ENOENT) {
 		/* No patch/nvm-config found, run with original fw/config */
 		set_bit(QCA_ROM_FW, &qca->flags);