Documentation/Changes: remove some really obsolete text

That file harkens back to the days of the big 2.4 -> 2.6 version jump,
and was based even then on older versions.  Some of it is just obsolete,
and Jesper Juhl points out that it talks about kernel versions 2.6 and
should be updated to 3.0.

Remove some obsolete text, and re-phrase some other to not be 2.6-specific.

Reported-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>