xfs: remove xlog_recover_iodone

Source kernel commit: 22c10589a10baea8e4695fcf38437b89a41e70a1

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>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>