Input: mousedev - correct lockdep annotation

When annotating mutex to avoid false lockdep reports we should not
be using MOUSEDEV_MIX as lock subclass but rather SINGLE_DEPTH_NESTING.

Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/mousedev.c b/drivers/input/mousedev.c
index d528a2d..9897334 100644
--- a/drivers/input/mousedev.c
+++ b/drivers/input/mousedev.c
@@ -866,7 +866,7 @@
 	spin_lock_init(&mousedev->client_lock);
 	mutex_init(&mousedev->mutex);
 	lockdep_set_subclass(&mousedev->mutex,
-			     minor == MOUSEDEV_MIX ? MOUSEDEV_MIX : 0);
+			     minor == MOUSEDEV_MIX ? SINGLE_DEPTH_NESTING : 0);
 	init_waitqueue_head(&mousedev->wait);
 
 	if (minor == MOUSEDEV_MIX)