[Yaffs] TODO list for Linux stuff

Hi YAFFSers

As I mentioned before, and did not get any negative reaction to, the YAFFS2
will become the "mainstream" and the YAFFS1 codebase will become stagnant.
YAFFS1 memory layout will still be supported through YAFFS2 backward
compatability.

This basic policy should allow things to proceed faster since testing etc will
only need to be done once.

I have a mini-todo list that I am working through for the Linux stuff.
Suggestions for additions/proioritsation welcome:

1) Finish off a few things in the pipe (recently tested, but not yet checked
in):
* Getting rid of the st_time compilation issue.
* Improving garbage collection performance when disk is full.
* A few tidy-ups

2) patchin etc to build yaffs2 into kernel.

3) Clean up for kernel integration, and get into kernel.

4) Sorting out a new POSIX-ness issues.

5) Some other speed-ups.

-- Charles