[PATCH] hide attr_smt_snooze_delay reference with CONFIG_PPC64

[Nathan Lynch]

Milton Miller wrote:
> attr_smt_snooze_delay is defined for CONFIG_PPC64, so protect the attribute
> removal with the same condition.
> 
> /data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c: In function ‘unregister_cpu_online’:
> /data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c:722: error: ‘attr_smt_snooze_delay’ undeclared (first use in this function)
> /data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c:722: error: (Each undeclared identifier is reported only once
> /data/home/miltonm/next.git/arch/powerpc/kernel/sysfs.c:722: error: for each function it appears in.)

Is this one going in?  The build is also broken for powermac 32-bit
SMP with HOTPLUG_CPU=y (which I can't figure out how to turn off,
grr).  And this isn't confined to -next; mainline is broken too.