oprofile: Adding switch counter to oprofile statistic variables

This patch moves the multiplexing switch counter from x86 code to
common oprofile statistic variables. Now the value will be available
and usable for all architectures. The initialization and
incrementation also moved to common code.

Signed-off-by: Robert Richter <robert.richter@amd.com>

drivers/oprofile/oprof.c

@@ -107,8 +107,11 @@ static void stop_switch_worker(void)
 
 static void switch_worker(struct work_struct *work)
 {
-	if (!oprofile_ops.switch_events())
-		start_switch_worker();
+	if (oprofile_ops.switch_events())
+		return;
+
+	atomic_inc(&oprofile_stats.multiplex_counter);
+	start_switch_worker();
 }
 
 /* User inputs in ms, converts to jiffies */