The generic irq affinity code limits us to a single cpu target regardless
of what the architecture supports.  If required this should be done in the
architecture specific ->set_affinity call.

With this patch ppc64 is able to select all cpus affinity again.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>