xfs: remove xlog_recover_iodone

The log recovery I/O completion handler does not substancially differ from
the normal one except for the fact that it:

 a) never retries failed writes
 b) can have log items that aren't on the AIL
 c) never has inode/dquot log items attached and thus don't need to
    handle them

Add conditionals for (a) and (b) to the ioend code, while (c) doesn't
need special handling anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>