powerpc/85xx: Make kexec to interate over online cpus

This is not strictly required, because this iterates over logical
cpus and they are not (currently) discontigous. But, it's cleaner
code and more obvious what is going on
Signed-off-by: NMatthew McClintock <msm@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

arch/powerpc/platforms/85xx/smp.c

@@ -207,7 +207,7 @@ static void mpc85xx_smp_machine_kexec(struct kimage *image)
 	if ( !timeout )
 		printk(KERN_ERR "Unable to bring down secondary cpu(s)");
 
-	for (i = 0; i < num_cpus; i++)
+	for_each_online_cpu(i)
 	{
 		if ( i == smp_processor_id() ) continue;
 		mpic_reset_core(i);