[Yaffs] Yaffs 4.8 compilation issues

Hi,
We're porting one of our systems to Linux 4.8, and we've noticed that Yaffs
doesn't seem to want to compile properly on it - there have been some
changes around xattr, get_link, and a few other bits & pieces.

Charles - can you have a look at https://github.com/AndreRenaud/yaffs, and
provide any feedback on whether this looks appropriate? We've only just
done preliminary testing at this stage.

Thanks,
Andre