f2fs: only set release for file that has compressed data

If a file is not comprssed yet or does not have compressed data,
for example, its data has a very low compression ratio, do not
set FI_COMPRESS_RELEASED flag.

Signed-off-by: Sheng Yong <shengyong@oppo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>