NFSv4/pnfs: Give nfs4_proc_layoutreturn() a flags argument

Replace the boolean in nfs4_proc_layoutreturn() with a set of flags that
will allow us to craft a version that is appropriate for reboot
recovery.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>