USB: legotower: fix logical error in recent commit

Commit d9f0d82f ("USB: legousbtower: use usb_control_msg_recv()")
contained an elementary logical error.  The check of the return code
from the new usb_control_msg_recv() function was inverted.

Reported-and-tested-by: syzbot+9be25235b7a69b24d117@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20201208163042.GD1298255@rowland.harvard.edu
Fixes: d9f0d82f ("USB: legousbtower: use usb_control_msg_recv()")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/misc/legousbtower.c

@@ -797,7 +797,7 @@ static int tower_probe(struct usb_interface *interface, const struct usb_device_
 				      &get_version_reply,
 				      sizeof(get_version_reply),
 				      1000, GFP_KERNEL);
-	if (!result) {
+	if (result) {
 		dev_err(idev, "get version request failed: %d\n", result);
 		retval = result;
 		goto error;