cpuidle: Annotate poll_idle()

The __cpuidle functions will become a noinstr class, as such they need
explicit annotations.

Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>
Tested-by: Tony Lindgren <[e-mail]>
Tested-by: Ulf Hansson <[e-mail]>
Reviewed-by: Rafael J. Wysocki <[e-mail]>
Acked-by: Frederic Weisbecker <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/cpuidle/poll_state.c

···
 static int __cpuidle poll_idle(struct cpuidle_device *dev,
 			       struct cpuidle_driver *drv, int index)
 {
-	u64 time_start = local_clock();
+	u64 time_start;
+
+	instrumentation_begin();
+	time_start = local_clock();
 
 	dev->poll_time_limit = false;
 
···
 	raw_local_irq_disable();
 
 	current_clr_polling();
+	instrumentation_end();
 
 	return index;
 }