topology: Provide CPU topology in sysfs in !SMP configurations

We should provide topology information to userland even if it's not
very interesting.  The current code appears to work properly for !SMP
(tested on i386).

Reference: http://bugs.debian.org/649216
Reported-by: Marcus Osdoba <marcus.osdoba@googlemail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>