Mostly revert "qemu-help: Sort devices by logical functionality"

Mostly revert "qemu-help: Sort devices by logical functionality"

This reverts most of commit 3d1237fb2ab4edb926c717767bb5e31d6053a7c5.

The commit claims to sort the output of "-device help" "by
functionality rather than alphabetical".  Issues:

* The output was unsorted before, not alphabetically sorted.
  Misleading, but harmless enough.

* The commit doesn't just sort the output of "-device help" as it
  claims, it adds categories to each line of "-device help", and it
  prints devices once per category.  In particular, devices without a
  category aren't shown anymore.  Maybe such devices should not exist,
  but they do.  Regression.

* Categories are also added to the output of "info qdm".  Silent
  change, not nice.  Output remains unsorted, unlike "-device help".

I'm going to reimplement the feature we actually want, without the
warts.  Reverting the flawed commit first should make it easier to
review.  However, I can't revert it completely, since DeviceClass
member categories has been put to use.  So leave that part in.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel.a@redhat.com>
Message-id: 1381410021-1538-2-git-send-email-armbru@redhat.com
Signed-off-by: Anthony Liguori <aliguori@amazon.com>