NFS: Filter cache invalidation when holding a delegation

If the client holds a delegation, then ensure we filter out attempts
to invalidate the size, owner, group owner, or mode unless we made the
change, in which case, check that NFS_INO_REVAL_FORCED is set by the
caller.
Always filter out attempts to invalidate the change attribute and
size, since we are authoritative for those.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>