[pnfs] Latest spnfs branch (and pnfs?) fails to compile

[Muntz, Daniel]

  CC      fs/nfs/pnfs.o
fs/nfs/pnfs.c: In function 'pnfs_layoutcommit_validate':
fs/nfs/pnfs.c:1814: error: implicit declaration of function
'nfs4_setup_sequence'

Which is related to this patch:

commit a389319f00aedfd398aee0d34142cb208c673258
Author: Benny Halevy <bhalevy at panasas.com>
Date:   Mon Jun 2 13:00:01 2008 +0300

    [SQUASHME] nfs41: make nfs4_setup_sequence static
    
    nfs4_setup_sequence is called only from pnfs code,
    which should actually use the nfs41_setup_sequence path
    (that doesn't recover then session) like all other async
    validate_seq_args call paths.
    
    Signed-off-by: Benny Halevy <bhalevy at panasas.com>

The same call to nfs4_setup_sequence appears in the pnfs branch as well.

  -Dan