Bluetooth: hci_qca: fix potential GPF

In qca_power_shutdown() qcadev local variable is
initialized by hu->serdev.dev private data, but
hu->serdev can be NULL and there is a check for it.

Since, qcadev is not used before

	if (!hu->serdev)
		return;

we can move its initialization after this "if" to
prevent GPF.

Fixes: 5559904c ("Bluetooth: hci_qca: Add QCA Rome power off support to the qca_power_shutdown()")
Cc: stable@vger.kernel.org # v5.6+
Cc: Rocky Liao <rjliao@codeaurora.org>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/hci_qca.c

@@ -1835,8 +1835,6 @@ static void qca_power_shutdown(struct hci_uart *hu)
 	unsigned long flags;
 	enum qca_btsoc_type soc_type = qca_soc_type(hu);
 
-	qcadev = serdev_device_get_drvdata(hu->serdev);
-
 	/* From this point we go into power off state. But serial port is
 	 * still open, stop queueing the IBS data and flush all the buffered
 	 * data in skb's.
@@ -1852,6 +1850,8 @@ static void qca_power_shutdown(struct hci_uart *hu)
 	if (!hu->serdev)
 		return;
 
+	qcadev = serdev_device_get_drvdata(hu->serdev);
+
 	if (qca_is_wcn399x(soc_type)) {
 		host_set_baudrate(hu, 2400);
 		qca_send_power_pulse(hu, false);