f2fs: update_sit_entry: Make the judgment condition of f2fs_bug_on more intuitive

Current judgment condition of f2fs_bug_on in function update_sit_entry():
  new_vblocks >> (sizeof(unsigned short) << 3) ||
	new_vblocks > sbi->blocks_per_seg

which equivalents to:
  new_vblocks < 0 || new_vblocks > sbi->blocks_per_seg

The latter is more intuitive.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reported-by: Jack Qiu <jack.qiu@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>