documentation: drop vmtruncate

Removed vmtruncate

Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 0742fee..0472c31 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -281,7 +281,7 @@
 
 [mandatory]
 
-	->truncate is going away.  The whole truncate sequence needs to be
+	->truncate is gone.  The whole truncate sequence needs to be
 implemented in ->setattr, which is now mandatory for filesystems
 implementing on-disk size changes.  Start with a copy of the old inode_setattr
 and vmtruncate, and the reorder the vmtruncate + foofs_vmtruncate sequence to