parisc: Fix crash with nr_cpus=1 option

John David Anglin reported that giving "nr_cpus=1" on the command
line causes a crash, while "maxcpus=1" works.
Reported-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v5.18+

arch/parisc/kernel/smp.c

@@ -440,7 +440,9 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 	if (cpu_online(cpu))
 		return 0;
 
-	if (num_online_cpus() < setup_max_cpus && smp_boot_one_cpu(cpu, tidle))
+	if (num_online_cpus() < nr_cpu_ids &&
+		num_online_cpus() < setup_max_cpus &&
+		smp_boot_one_cpu(cpu, tidle))
 		return -EIO;
 
 	return cpu_online(cpu) ? 0 : -EIO;