f2fs: change return value of f2fs_disable_compressed_file to bool

The returned integer is not required anywhere. So we need to change
the return value to bool type.

Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>