s390/sclp: replace deprecated CPU-hotplug functions

The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20210803141621.780504-6-bigeasy@linutronix.deSigned-off-by: NHeiko Carstens <hca@linux.ibm.com>

drivers/s390/char/sclp_config.c

@@ -50,12 +50,12 @@ static void sclp_cpu_capability_notify(struct work_struct *work)
 
 	s390_update_cpu_mhz();
 	pr_info("CPU capability may have changed\n");
-	get_online_cpus();
+	cpus_read_lock();
 	for_each_online_cpu(cpu) {
 		dev = get_cpu_device(cpu);
 		kobject_uevent(&dev->kobj, KOBJ_CHANGE);
 	}
-	put_online_cpus();
+	cpus_read_unlock();
 }
 
 static void __ref sclp_cpu_change_notify(struct work_struct *work)