USB: legousbtower: fix a signedness bug in tower_probe()

The problem is that sizeof() is unsigned long so negative error codes
are type promoted to high positive values and the condition becomes
false.

Fixes: 1d427be4 ("USB: legousbtower: fix slab info leak at probe")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191011141115.GA4521@mwandaSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/misc/legousbtower.c

@@ -878,7 +878,7 @@ static int tower_probe (struct usb_interface *interface, const struct usb_device
 				  get_version_reply,
 				  sizeof(*get_version_reply),
 				  1000);
-	if (result < sizeof(*get_version_reply)) {
+	if (result != sizeof(*get_version_reply)) {
 		if (result >= 0)
 			result = -EIO;
 		dev_err(idev, "get version request failed: %d\n", result);