f2fs: check hot_data for roll-forward recovery

commit 125c9fb1ccb53eb2ea9380df40f3c743f3fb2fed upstream.

We need to check HOT_DATA to truncate any previous data block when doing
roll-forward recovery.

Cc: <stable@vger.kernel.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>