usbip: vudc: Fix apparent cut-n-paste error

Coverity picked up that this looks like a cut-n-paste from an almost
identical sequence below that didn't get its variable renamed.
Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/usbip/vudc_dev.c

@@ -450,7 +450,7 @@ static void vudc_shutdown(struct usbip_device *ud)
 	if (ud->tcp_socket)
 		kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
 
-	if (ud->tcp_tx) {
+	if (ud->tcp_rx) {
 		kthread_stop_put(ud->tcp_rx);
 		ud->tcp_rx = NULL;
 	}