xfs: remove XFS_BUF_TO_SBP

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: Brian Foster <bfoster@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/scrub/agheader.c

@@ -92,7 +92,7 @@ xchk_superblock(
 	if (!xchk_process_error(sc, agno, XFS_SB_BLOCK(mp), &error))
 		return error;
 
-	sb = XFS_BUF_TO_SBP(bp);
+	sb = bp->b_addr;
 
 	/*
 	 * Verify the geometries match.  Fields that are permanently

fs/xfs/scrub/agheader_repair.c

@@ -49,7 +49,7 @@ xrep_superblock(
 
 	/* Copy AG 0's superblock to this one. */
 	xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
-	xfs_sb_to_disk(XFS_BUF_TO_SBP(bp), &mp->m_sb);
+	xfs_sb_to_disk(bp->b_addr, &mp->m_sb);
 
 	/* Write this to disk. */
 	xfs_trans_buf_set_type(sc->tp, bp, XFS_BLFT_SB_BUF);