[XFS] embededd struct xfs_imap into xfs_inode

Most uses of struct xfs_imap are to map and inode to a buffer.  To avoid
copying around the inode location information we should just embedd a
strcut xfs_imap into the xfs_inode.  To make sure it doesn't bloat an
inode the im_len is changed to a ushort, which is fine as that's what
the users exepect anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Niv Sardi <xaiki@sgi.com>

fs/xfs/xfs_itable.c

@@ -69,7 +69,7 @@ xfs_bulkstat_one_iget(
 	}
 
 	ASSERT(ip != NULL);
-	ASSERT(ip->i_blkno != (xfs_daddr_t)0);
+	ASSERT(ip->i_imap.im_blkno != 0);
 
 	dic = &ip->i_d;