carl9170: fix leaks at failure path in carl9170_usb_probe()

carl9170_usb_probe() does not handle request_firmware_nowait() failure
that leads to several leaks in this case.
The patch adds all required deallocations.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/carl9170/usb.c

@@ -1076,8 +1076,14 @@ static int carl9170_usb_probe(struct usb_interface *intf,
 
 	carl9170_set_state(ar, CARL9170_STOPPED);
 
-	return request_firmware_nowait(THIS_MODULE, 1, CARL9170FW_NAME,
+	err = request_firmware_nowait(THIS_MODULE, 1, CARL9170FW_NAME,
 		&ar->udev->dev, GFP_KERNEL, ar, carl9170_usb_firmware_step2);
+	if (err) {
+		usb_put_dev(udev);
+		usb_put_dev(udev);
+		carl9170_free(ar);
+	}
+	return err;
 }
 
 static void carl9170_usb_disconnect(struct usb_interface *intf)