It needs to add missing gcing flag on page during block migration,
in order to garantee migrated data be persisted during checkpoint,
otherwise out-of-order persistency between data and node may cause
data corruption after SPOR.

Similar issue was fixed by commit 2d1fe8a8 ("f2fs: fix to tag
gcing flag on page during file defragment").
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>