MIPS: CPU#0 is not hotpluggable

BugLink: https://bugs.launchpad.net/bugs/1892822

commit 9cce844a upstream.

Now CPU#0 is not hotpluggable on MIPS, so prevent to create /sys/devices
/system/cpu/cpu0/online which confuses some user-space tools.

Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

arch/mips/kernel/topology.c

@@ -19,7 +19,7 @@ static int __init topology_init(void)
 	for_each_present_cpu(i) {
 		struct cpu *c = &per_cpu(cpu_devices, i);
 
-		c->hotpluggable = 1;
+		c->hotpluggable = !!i;
 		ret = register_cpu(c, i);
 		if (ret)
 			printk(KERN_WARNING "topology_init: register_cpu %d "