[POWERPC] powermac: local_irq_disable() is redundant after local_irq_save()

arch/powerpc/platforms/powermac/smp.c::smp_core99_kick_cpu() contains
local_irq_disable() call after local_irq_save(). This looks
redundant.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Paul Mackerras <paulus@samba.org>