Input: poller - convert locking to guard notation

Use guard() notation instead of explicitly acquiring and releasing
mutex to simplify the code and ensure that it is released.

Link: https://lore.kernel.org/r/20241107071538.195340-8-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: dtor

drivers/input/input-poller.c

@@ -162,7 +162,7 @@ static ssize_t input_dev_set_poll_interval(struct device *dev,
 	if (interval > poller->poll_interval_max)
 		return -EINVAL;
 
-	mutex_lock(&input->mutex);
+	guard(mutex)(&input->mutex);
 
 	poller->poll_interval = interval;
 
@@ -172,8 +172,6 @@ static ssize_t input_dev_set_poll_interval(struct device *dev,
 			input_dev_poller_queue_work(poller);
 	}
 
-	mutex_unlock(&input->mutex);
-
 	return count;
 }