s390/pai: cleanup event initialization

Setting event::hw.last_tag to zero is not necessary. The memory
for each event is dynamically allocated by the kernel common code and
initialized to zero already.  Remove this unnecessary assignment.
Move the comment to function paicrypt_start() for clarification.
Suggested-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

arch/s390/kernel/perf_pai_crypto.c

@@ -279,12 +279,6 @@ static int paicrypt_event_init(struct perf_event *event)
 	if (IS_ERR(cpump))
 		return PTR_ERR(cpump);
 
-	/* Event initialization sets last_tag to 0. When later on the events
-	 * are deleted and re-added, do not reset the event count value to zero.
-	 * Events are added, deleted and re-added when 2 or more events
-	 * are active at the same time.
-	 */
-	event->hw.last_tag = 0;
 	event->destroy = paicrypt_event_destroy;
 
 	if (a->sample_period) {
@@ -318,6 +312,11 @@ static void paicrypt_start(struct perf_event *event, int flags)
 {
 	u64 sum;
 
+	/* Event initialization sets last_tag to 0. When later on the events
+	 * are deleted and re-added, do not reset the event count value to zero.
+	 * Events are added, deleted and re-added when 2 or more events
+	 * are active at the same time.
+	 */
 	if (!event->hw.last_tag) {
 		event->hw.last_tag = 1;
 		sum = paicrypt_getall(event);		/* Get current value */

arch/s390/kernel/perf_pai_ext.c

@@ -260,7 +260,6 @@ static int paiext_event_init(struct perf_event *event)
 	rc = paiext_alloc(a, event);
 	if (rc)
 		return rc;
-	event->hw.last_tag = 0;
 	event->destroy = paiext_event_destroy;
 
 	if (a->sample_period) {