linux-phytec-fsl

NFS: Add nfs_commit_file()

Copy will use this to set up a commit request for a generic range.  I
don't want to allocate a new pagecache entry for the file, so I needed
to change parts of the commit path to handle requests with a null
wb_page.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>