Update email address

Redirect some older email addresses that are in the git logs.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index 2dfc800..9e4c868 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -4,7 +4,7 @@
 /*
  * eXtensible Arrays
  * Copyright (c) 2017 Microsoft Corporation
- * Author: Matthew Wilcox <mawilcox@microsoft.com>
+ * Author: Matthew Wilcox <willy@infradead.org>
  */
 
 #include <linux/spinlock.h>