nilfs2: remove useless b_low and b_high fields from nilfs_bmap struct

This will cut off 16 bytes from the nilfs_bmap struct which is
embedded in the on-memory inode of nilfs.

The b_high field was never used, and the b_low field stores a constant
value which can be determined by whether the inode uses btree for
block mapping or not.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/direct.h b/fs/nilfs2/direct.h
index 45d2c5c..d645f13 100644
--- a/fs/nilfs2/direct.h
+++ b/fs/nilfs2/direct.h
@@ -70,9 +70,9 @@
 #define NILFS_DIRECT_KEY_MAX	(NILFS_DIRECT_NBLOCKS - 1)
 
 
-int nilfs_direct_init(struct nilfs_bmap *, __u64, __u64);
+int nilfs_direct_init(struct nilfs_bmap *);
 int nilfs_direct_delete_and_convert(struct nilfs_bmap *, __u64, __u64 *,
-				    __u64 *, int, __u64, __u64);
+				    __u64 *, int);
 
 
 #endif	/* _NILFS_DIRECT_H */