x86: revert CONFIG_X86_HT semantics change

The recent Kconfig changes in x86 resulted in CONFIG_X86_HT no longer
being set if (X86_32 && MK8).

After grep'ing through the tree I think the problem is that different
places have different assumptions about the semantics of CONFIG_X86_HT,
either:

- hyperthreading or
- multicore

This should be sorted out properly, but until then we should keep the
2.6.23 status quo.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>