Impact: cleanup
There's one obvious place to use it: to find the highest possible cpu.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
 static void __init setup_nr_cpu_ids(void)
 {
-       int cpu, highest_cpu = 0;
-
-       for_each_possible_cpu(cpu)
-               highest_cpu = cpu;
-
-       nr_cpu_ids = highest_cpu + 1;
+       nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
 }
 
 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA