usb: gadget: pxa27x: Test for a valid argument pointer

A call usb_put_phy(udc->transceiver) must be tested for a valid pointer.
Use an already existing test for usb_unregister_notifier call.
Acked-by: NRobert Jarzmik <robert.jarzmik@free.fr>
Reported-by: NRobert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: NPetr Cvek <petr.cvek@tul.cz>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/udc/pxa27x_udc.c

@@ -2534,9 +2534,10 @@ static int pxa_udc_remove(struct platform_device *_dev)
 	usb_del_gadget_udc(&udc->gadget);
 	pxa_cleanup_debugfs(udc);
 
-	if (!IS_ERR_OR_NULL(udc->transceiver))
+	if (!IS_ERR_OR_NULL(udc->transceiver)) {
 		usb_unregister_notifier(udc->transceiver, &pxa27x_udc_phy);
-	usb_put_phy(udc->transceiver);
+		usb_put_phy(udc->transceiver);
+	}
 
 	udc->transceiver = NULL;
 	the_controller = NULL;