Revert "powerpc: Secondary CPUs must set cpu_callin_map after setting active and online"

This reverts commit 7c5c92ed56d932b2c19c3f8aea86369509407d33.

Although this did fix the bug it was aimed at, it also broke secondary
startup on platforms that use give/take_timebase(). Unfortunately we
didn't detect that while it was in next.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/smp.c

@@ -700,6 +700,7 @@ void start_secondary(void *unused)
 	smp_store_cpu_info(cpu);
 	set_dec(tb_ticks_per_jiffy);
 	preempt_disable();
+	cpu_callin_map[cpu] = 1;
 
 	if (smp_ops->setup_cpu)
 		smp_ops->setup_cpu(cpu);
@@ -738,14 +739,6 @@ void start_secondary(void *unused)
 	notify_cpu_starting(cpu);
 	set_cpu_online(cpu, true);
 
-	/*
-	 * CPU must be marked active and online before we signal back to the
-	 * master, because the scheduler needs to see the cpu_online and
-	 * cpu_active bits set.
-	 */
-	smp_wmb();
-	cpu_callin_map[cpu] = 1;
-
 	local_irq_enable();
 
 	cpu_startup_entry(CPUHP_ONLINE);