[XFS] no longer using io_vnode, as was remaining from 23 cherrypick

Because we cherrypicked SGI-Modid xfs-linux-melb:xfs-kern:29675a
and it depended on the sgi mod which removed io_vnode (which was
not cherrypicked in 23) it was hand modified.
This fixes things back up (to the originial mod) now we have moved
on again.
Reviewed-by: NLachlan McIlroy <lachlan@sgi.com>
Signed-off-by: NTim Shimmin <tes@sgi.com>

fs/xfs/linux-2.6/xfs_aops.c

@@ -180,7 +180,7 @@ xfs_setfilesize(
 		ip->i_d.di_size = isize;
 		ip->i_update_core = 1;
 		ip->i_update_size = 1;
-		mark_inode_dirty_sync(vn_to_inode(ioend->io_vnode));
+		mark_inode_dirty_sync(ioend->io_inode);
 	}
 
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);