[POWERPC] ps3: smp interrupt fixes

PS3 fixups for interrups on SMP.

Fixes the alignment of the interrupt status bitmap, changes the hypervisor
interrupt calls to the '_ext' versions that take an explicit processor
thread ID.

Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>