fsck.f2fs: fix double free invalid checkpoint
fsck.f2fs: fix double free invalid checkpoint

The invalid checkpoin is freed in validate_checkpoint().

Change-Id: I9025683078e7c2c99695d8f098aef9864e215c67
Signed-off-by: Sheng Yong <ce77ec10379c6f281208b7b41f03fd701be51d81@huawei.com>
Signed-off-by: Jaegeuk Kim <71255387a32c360dfbe6dfb7aaeb123bf1dc8cb6@kernel.org>

PAC-ROM/android_external_f2fs-tools,blastagator/cm_external_f2fs-tools,PAC-ROM/android_external_f2fs-tools,blastagator/cm_external_f2fs-tools