[XFS] Remove the BPCSHIFT and NB* based macros from XFS.

The BPCSHIFT based macros, btoc*, ctob*, offtoc* and ctooff are either not
used or don't need to be used. The NDPP, NDPP, NBBY macros don't need to
be used but instead are replaced directly by PAGE_SIZE and PAGE_CACHE_SIZE
where appropriate. Initial patch and motivation from Nicolas Kaiser.

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:30096a

Signed-off-by: Tim Shimmin <tes@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index aca51e7..1c0a5a5 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -2830,11 +2830,11 @@
 		args.prod = align;
 		if ((args.mod = (xfs_extlen_t)do_mod(ap->off, args.prod)))
 			args.mod = (xfs_extlen_t)(args.prod - args.mod);
-	} else if (mp->m_sb.sb_blocksize >= NBPP) {
+	} else if (mp->m_sb.sb_blocksize >= PAGE_CACHE_SIZE) {
 		args.prod = 1;
 		args.mod = 0;
 	} else {
-		args.prod = NBPP >> mp->m_sb.sb_blocklog;
+		args.prod = PAGE_CACHE_SIZE >> mp->m_sb.sb_blocklog;
 		if ((args.mod = (xfs_extlen_t)(do_mod(ap->off, args.prod))))
 			args.mod = (xfs_extlen_t)(args.prod - args.mod);
 	}