[POWERPC] 86xx: local_irq_disable() is redundant after local_irq_save()

arch/powerpc/platforms/86xx/mpc86xx_smp.c::smp_86xx_kick_cpu() contains
local_irq_disable() call after local_irq_save(). This looks
redundant.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>