xen/evtchn: double free on error

The call to del_evtchn() frees "evtchn".

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/evtchn.c

@@ -319,7 +319,6 @@ err:
 	if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 		BUG();
 	del_evtchn(u, evtchn);
-	kfree(evtchn);
 	return rc;
 }