perf: Simplify task_clock_event_read()

There is no point in us having different code paths for nmi and !nmi
here, so remove the !nmi one.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/perf_event.c

@@ -5810,16 +5810,9 @@ static void task_clock_event_del(struct perf_event *event, int flags)
 
 static void task_clock_event_read(struct perf_event *event)
 {
-	u64 time;
-
-	if (!in_nmi()) {
-		update_context_time(event->ctx);
-		time = event->ctx->time;
-	} else {
-		u64 now = perf_clock();
-		u64 delta = now - event->ctx->timestamp;
-		time = event->ctx->time + delta;
-	}
+	u64 now = perf_clock();
+	u64 delta = now - event->ctx->timestamp;
+	u64 time = event->ctx->time + delta;
 
 	task_clock_event_update(event, time);
 }