f2fs: fix the size value in __check_sit_bitmap

commit 008396e1b026b3873091b555b808155da7d9d18f upstream.

The current size value is not correct and will miss bitmap check.

Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Git-commit: 2f9f8a0b
Git-repo: https://android.googlesource.com/kernel/common.git


Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>