NFSv4.1: Cleanup; add "pnfs_" prefix to get_layout_hdr() and put_layout_hdr()

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --cc fs/nfs/callback_proc.c
Simple merge

diff --cc fs/nfs/nfs4proc.c
Simple merge

diff --cc fs/nfs/pnfs.c
Simple merge

diff --cc fs/nfs/pnfs.h
Simple merge