In SB600, the IOAPIC is allocated in sb600_sm.c. Is there any conflict with sb600_lpc.c?
It was just for backward compatibility. I put a fixed allocation at 0xfec00000 in most boards because that's where it used to be. If there's nothing that needs to be protected there, you can remove it. You'd probably need one for the local APICs for the processors, though.
Sorry for the confusion.