xfs: remove XFS_BUF_TO_AGI

Just dereference bp->b_addr directly and make the code a little
simpler and more clear.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 3324e16..addc3ee 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2117,7 +2117,7 @@ xfs_iunlink_update_bucket(
 	unsigned int		bucket_index,
 	xfs_agino_t		new_agino)
 {
-	struct xfs_agi		*agi = XFS_BUF_TO_AGI(agibp);
+	struct xfs_agi		*agi = agibp->b_addr;
 	xfs_agino_t		old_value;
 	int			offset;
 
@@ -2257,7 +2257,7 @@ xfs_iunlink(
 	error = xfs_read_agi(mp, tp, agno, &agibp);
 	if (error)
 		return error;
-	agi = XFS_BUF_TO_AGI(agibp);
+	agi = agibp->b_addr;
 
 	/*
 	 * Get the index into the agi hash table for the list this inode will
@@ -2441,7 +2441,7 @@ xfs_iunlink_remove(
 	error = xfs_read_agi(mp, tp, agno, &agibp);
 	if (error)
 		return error;
-	agi = XFS_BUF_TO_AGI(agibp);
+	agi = agibp->b_addr;
 
 	/*
 	 * Get the index into the agi hash table for the list this inode will