type: make pointers unsigned

type: make pointers unsigned

In Sparse pointers are special and neither the signed nor the unsigned
bit is set.  By chance, I happened to make them signed in Smatch and then
I didn't change it because it was handy to have error pointer show up as
negatives.

But really pointers are unsigned.  So I have bit the bullet and changed it.
Part of what made me do this is the work with mtags.

One of the ideas that I had had was that the various segments and the stack
and the heap would all be indicated by the pointer range.  I never
implemented any checks which used this and really it never worked well.
You would get an unknown pointer and mark it as a general valid pointer
and that was that.

Then when I started using mtags, not all of them were in the valid pointer
range.

One thing I did is that error pointer are still marked as negative, but
they're at the high value side of the range instead of in front or middle.
It looks like this:  "0,4096-ptr_max,(-22),(-12)".

I've been running with this code for a while now and it seems basically
okay.  Hopefully, I manage to commit all the necessary parts.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>