xfs: remove another leftover of the old inode log item format

There's another little snipplet of code left from the handling of the old
inode log item format in xlog_recover_do_inode_trans.  Kill it as it
can't be reached anymore.

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