nfsd: formally deprecate legacy nfsd syscall interface

The syscall interface is has been replaced by a more flexible
interface since 2.6.0.  It is time to work towards discarding
the old interface.

So add a entry in feature-removal-schedule.txt and print a warning
when the interface is used.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 842aa9d..076a2c0 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -564,3 +564,13 @@
 
 ----------------------------
 
+What:   access to nfsd auth cache through sys_nfsservctl or '.' files
+        in the 'nfsd' filesystem.
+When:   2.6.40
+Why:    This is a legacy interface which have been replaced by a more
+        dynamic cache.  Continuing to maintain this interface is an
+        unnecessary burden.
+Who:    NeilBrown <neilb@suse.de>
+
+----------------------------
+