oprofile uses smp_num_siblings without testing for CONFIG_X86_HT.
I looked at modifying oprofile, but this way is cleaner & simpler
and I didn't see a good reason not to just export it when CONFIG_SMP.

WARNING: "smp_num_siblings" [arch/i386/oprofile/oprofile.ko] undefined!
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andi Kleen <ak@suse.de>