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

[Dave Jones]

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 <da...@codemonkey.org.uk>

diff --git a/drivers/usb/usbip/vudc_dev.c b/drivers/usb/usbip/vudc_dev.c
index 8994a13819ab..7091848df6c8 100644
--- a/drivers/usb/usbip/vudc_dev.c
+++ b/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;
        }