Use shifts in nilfs2.

	Use shifts in nilfs2.

	* grub-core/fs/nilfs2.c (LOG_INODE_SIZE): New definition.
	(LOG_NILFS_DAT_ENTRY_SIZE): Likewise.
	(grub_nilfs2_palloc_entries_per_group): Replace with ...
	(grub_nilfs2_log_palloc_entries_per_group): ... this.
	(grub_nilfs2_palloc_group): Use shifts and bitmasks.
	(grub_nilfs2_entries_per_block): Replaced with ...
	(grub_nilfs2_log_entries_per_block_log): ... this.
	(grub_nilfs2_blocks_per_group): Replaced with ...
	(grub_nilfs2_blocks_per_group_log): ... this.
	(grub_nilfs2_blocks_per_desc_block): Replaced with ...
	(grub_nilfs2_blocks_per_desc_block_log): ... this.
	(grub_nilfs2_palloc_desc_block_offset): Replaced with ...
	(grub_nilfs2_palloc_desc_block_offset_log): ... this.
	(grub_nilfs2_palloc_entry_offset): Replaced ...
	(grub_nilfs2_palloc_entry_offset_log): ... this. Use shifts.
	(grub_nilfs2_dat_translate): Use shifts.
	(grub_nilfs2_read_inode): Likewise.
	(GRUB_MOD_INIT): Ensure that logs are correct.