Input: maple_keyb - use guard notation when acquiring mutex

Using guard notation makes the code more compact and error handling
more robust by ensuring that mutexes are released in all code paths
when control leaves critical section.

Link: https://lore.kernel.org/r/Zx8mGiWOw1Av28TX@google.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: dtor

drivers/input/keyboard/maple_keyb.c

@@ -132,14 +132,11 @@ static void dc_kbd_callback(struct mapleq *mq)
 	 * We should always get the lock because the only
 	 * time it may be locked is if the driver is in the cleanup phase.
 	 */
-	if (likely(mutex_trylock(&maple_keyb_mutex))) {
-
+	scoped_guard(mutex_try, &maple_keyb_mutex) {
 		if (buf[1] == mapledev->function) {
 			memcpy(kbd->new, buf + 2, 8);
 			dc_scan_kbd(kbd);
 		}
-
-		mutex_unlock(&maple_keyb_mutex);
 	}
 }
 
@@ -211,14 +208,12 @@ static int remove_maple_kbd(struct device *dev)
 	struct maple_device *mdev = to_maple_dev(dev);
 	struct dc_kbd *kbd = maple_get_drvdata(mdev);
 
-	mutex_lock(&maple_keyb_mutex);
+	guard(mutex)(&maple_keyb_mutex);
 
 	input_unregister_device(kbd->dev);
 	kfree(kbd);
 
 	maple_set_drvdata(mdev, NULL);
-
-	mutex_unlock(&maple_keyb_mutex);
 	return 0;
 }