f2fs: remove unused function overprovision_sections

commit f24b150a63b208f4437efc7dc7a42954363641ca upstream.

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: 7b784f45
Git-repo: https://android.googlesource.com/kernel/common.git


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