resize.f2fs: fix max_nat_bitmap_size miscalculatation

For the same reason as "mkfs.f2fs: fix to calculate
left space of checkpoint page correctly",
this patch also fixes miscalculatation in resize.f2fs.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
3 files changed