- send_ipi_message() fix from Jeff Wiedemeier:
  The 2.5.30 IPI algorithm (with the to_whom == set test) incorrectly sends
  IPI messages to CPU 0 in a SMP system running with one processor. In this
  case to_whom is often 0 (cpu_present_mask & ~1UL << smp_processor_id()) which
  ends up triggering the to_whom == set case.
- migration IPI removed;