NFSv4: Only pass the delegation to setattr if we're sending a truncate

commit 991eedb1 upstream.

Even then it isn't really necessary. The reason why we may not want to
pass in a stateid in other cases is that we cannot use the delegation
credential.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>