[S390] prevent unneccesary loops_per_jiffy recalculation

When the seqfile /proc/cpuinfo gets accesses for each possible cpu
loops_per_jiffy gets recalculated. However its value is only needed
on first access.
In addition loops_per_jiffy should be recalculated when the machine
reports a capability change.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/processor.c

@@ -46,8 +46,8 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 	unsigned long n = (unsigned long) v - 1;
 	int i;
 
-	s390_adjust_jiffies();
 	if (!n) {
+		s390_adjust_jiffies();
 		seq_printf(m, "vendor_id       : IBM/S390\n"
 			   "# processors    : %i\n"
 			   "bogomips per cpu: %lu.%02lu\n",

drivers/s390/char/sclp_config.c

@@ -33,6 +33,7 @@ static void sclp_cpu_capability_notify(struct work_struct *work)
 	int cpu;
 	struct sys_device *sysdev;
 
+	s390_adjust_jiffies();
 	pr_warning("cpu capability changed.\n");
 	get_online_cpus();
 	for_each_online_cpu(cpu) {