usb: usbip: remove redundant pointer ep

Pointer ep is being assigned but is never used hence it is
redundant and can be removed.

Cleans up clang warning:
warning: variable 'ep' set but not used [-Wunused-but-set-variable]
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/usbip/vudc_dev.c

@@ -279,12 +279,10 @@ static int vep_disable(struct usb_ep *_ep)
 static struct usb_request *vep_alloc_request(struct usb_ep *_ep,
 		gfp_t mem_flags)
 {
-	struct vep *ep;
 	struct vrequest *req;
 
 	if (!_ep)
 		return NULL;
-	ep = to_vep(_ep);
 
 	req = kzalloc(sizeof(*req), mem_flags);
 	if (!req)