domain setup in 2.6.9rc1-bk6

Someone deleted arch/x86_64/kernel/domain.c in current BK 
and moved the SMT domain setup to generic code.

Problem is that I need a architecture specific hook to 
turn off SMT idle for AMD dual core CPUs, which otherwise
look like SMT siblings. I suppose I will do more tunings
in this area in the future anyways, so having it in the 
architecture would be better.

It seems a bit counterintuitive that we have such a configurable
scheduler, and then there is only a "one size fits all" way
to configure it.

Can part of this code please be moved back to the architecture? 

Thanks,

-Andi