powerpc: kernel: remove useless code which related with 'max_cpus'

Since not need 'max_cpus' after the related commit, the related code
are useless too, need be removed.

The related commit:

  c1aa687d powerpc: Clean up obsolete code relating to decrementer and timebase

The related warning:

  arch/powerpc/kernel/smp.c:323:43: warning: parameter ‘max_cpus’ set but not used [-Wunused-but-set-parameter]
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/smp.c

@@ -369,13 +369,8 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
 	cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
 
-	if (smp_ops)
-		if (smp_ops->probe)
-			max_cpus = smp_ops->probe();
-		else
-			max_cpus = NR_CPUS;
-	else
-		max_cpus = 1;
+	if (smp_ops && smp_ops->probe)
+		smp_ops->probe();
 }
 
 void smp_prepare_boot_cpu(void)