ocfs: stop using do_sync_mapping_range

do_sync_mapping_range(..., SYNC_FILE_RANGE_WRITE) is a very awkward way
to perform a filemap_fdatawrite_range.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>