cpumask: use set_cpu_active in init/main.c

cpu_active_map is deprecated in favor of cpu_active_mask, which is
const for safety: we use accessors now (set_cpu_active) is we really
want to make a change.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 79e40f0..395b697 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -281,7 +281,7 @@
 		goto out;
 	}
 
-	cpu_clear(cpu, cpu_active_map);
+	set_cpu_active(cpu, false);
 
 	/*
 	 * Make sure the all cpus did the reschedule and are not
@@ -296,7 +296,7 @@
 	err = _cpu_down(cpu, 0);
 
 	if (cpu_online(cpu))
-		cpu_set(cpu, cpu_active_map);
+		set_cpu_active(cpu, true);
 
 out:
 	cpu_maps_update_done();
@@ -333,7 +333,7 @@
 		goto out_notify;
 	BUG_ON(!cpu_online(cpu));
 
-	cpu_set(cpu, cpu_active_map);
+	set_cpu_active(cpu, true);
 
 	/* Now call notifier in preparation. */
 	raw_notifier_call_chain(&cpu_chain, CPU_ONLINE | mod, hcpu);