hfsplus: do not cache and write next_alloc

We never look at it, nor change the next_alloc field in the superblock.  So
don't bother caching it or writing it out in hfsplus_sync_fs.
Signed-off-by: Christoph Hellwig <hch@tuxera.com>

fs/hfsplus/hfsplus_fs.h

@@ -129,7 +129,6 @@ struct hfsplus_sb_info {
 	int alloc_blksz_shift;
 	u32 total_blocks;
 	u32 free_blocks;
-	u32 next_alloc;
 	u32 next_cnid;
 	u32 file_count;
 	u32 folder_count;

fs/hfsplus/super.c

@@ -164,7 +164,6 @@ int hfsplus_sync_fs(struct super_block *sb, int wait)
 	sb->s_dirt = 0;
 
 	vhdr->free_blocks = cpu_to_be32(sbi->free_blocks);
-	vhdr->next_alloc = cpu_to_be32(sbi->next_alloc);
 	vhdr->next_cnid = cpu_to_be32(sbi->next_cnid);
 	vhdr->folder_count = cpu_to_be32(sbi->folder_count);
 	vhdr->file_count = cpu_to_be32(sbi->file_count);
@@ -355,7 +354,6 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 	}
 	sbi->total_blocks = be32_to_cpu(vhdr->total_blocks);
 	sbi->free_blocks = be32_to_cpu(vhdr->free_blocks);
-	sbi->next_alloc = be32_to_cpu(vhdr->next_alloc);
 	sbi->next_cnid = be32_to_cpu(vhdr->next_cnid);
 	sbi->file_count = be32_to_cpu(vhdr->file_count);
 	sbi->folder_count = be32_to_cpu(vhdr->folder_count);