x86/topology: convert to use arch_cpu_is_hotpluggable()

Convert x86 to use the arch_cpu_is_hotpluggable() helper rather than
arch_register_cpu().
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R3w-00Cszy-6k@rmk-PC.armlinux.org.ukSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/x86/kernel/topology.c

@@ -36,11 +36,8 @@
 #include <asm/cpu.h>
 
 #ifdef CONFIG_HOTPLUG_CPU
-int arch_register_cpu(int cpu)
+bool arch_cpu_is_hotpluggable(int cpu)
 {
-	struct cpu *c = per_cpu_ptr(&cpu_devices, cpu);
-
-	c->hotpluggable = cpu > 0;
-	return register_cpu(c, cpu);
+	return cpu > 0;
 }
 #endif /* CONFIG_HOTPLUG_CPU */