xfs: simplify xfs_chain_bio

Move setting up operation and write hint to xfs_alloc_ioend, and
then just copy over all needed information from the previous bio
in xfs_chain_bio and stop passing various parameters to it.

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>