[XFS] remove dead code for old inode item recovery

We have removed the support for old-style inode items a while ago and
xlog_recover_do_inode_trans is now only called for XFS_LI_INODE items.
That means we can remove the call to xfs_imap there and with it the
XFS_IMAP_LOOKUP that is set by all other callers.  We can also mark
xfs_imap static now.

(First sent on October 21st)

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