[XFS] kill the v_flag member in struct bhv_vnode

All flags previously handled at the vnode level are not in the xfs_inode
where we already have a flags mechanisms and free bits for flags
previously in the vnode.

SGI-PV: 969608
SGI-Modid: xfs-linux-melb:xfs-kern:29495a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>