xen: Replace lkml.org links with lore

As started by commit 05a5f51c ("Documentation: Replace lkml.org
links with lore"), replace lkml.org links with lore to better use a
single source that's more likely to stay available long-term.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210210234618.2734785-1-keescook@chromium.orgSigned-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

drivers/xen/xen-acpi-processor.c

@@ -3,7 +3,8 @@
  * Copyright 2012 by Oracle Inc
  * Author: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
  *
- * This code borrows ideas from https://lkml.org/lkml/2011/11/30/249
+ * This code borrows ideas from
+ * https://lore.kernel.org/lkml/1322673664-14642-6-git-send-email-konrad.wilk@oracle.com
  * so many thanks go to Kevin Tian <kevin.tian@intel.com>
  * and Yu Ke <ke.yu@intel.com>.
  */