[POWERPC] ps3: bind interrupt to cpu

Change the PS3 irq allocation routines to take an argument indicating which
cpu (processor thread) the interrupt should be serviced on.

The current system configuration favors device interrupts that are serviced
on cpu0, so that is used as the default.

Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>