[PATCH] Doc: update oops-tracing.txt (Tainted flags)

Update Documentation/oops-tracing.txt:

- add descriptions of 3 more "Tainted" flags;
- fix some typos;

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>