xfs: remove dfops parameter from ifree call stack

The inode free callchain starting in xfs_inactive_ifree() already
associates its dfops with the transaction. It still passes the dfops
on the stack down through xfs_difree_inobt(), however.

Clean up the call stack and reference dfops directly from the
transaction. This patch does not change behavior.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-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>