nfs: Add DEALLOCATE support

This patch adds support for using the NFS v4.2 operation DEALLOCATE to
punch holes in a file.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --cc fs/nfs/nfs42.h
Simple merge

diff --cc fs/nfs/nfs42proc.c
Simple merge

diff --cc fs/nfs/nfs42xdr.c
Simple merge

diff --cc fs/nfs/nfs4file.c
Simple merge

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

diff --cc fs/nfs/nfs4xdr.c
Simple merge

diff --cc include/linux/nfs4.h
Simple merge

diff --cc include/linux/nfs_fs_sb.h
Simple merge