ALSA: Avoid endless sleep after disconnect

When disconnect callback is called, each component should wake up
sleepers and check card->shutdown flag for avoiding the endless sleep
blocking the proper resource release.

Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/control.c b/sound/core/control.c
index 9768a39..8c7c2c9 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -1437,6 +1437,8 @@
 			spin_unlock_irq(&ctl->read_lock);
 			schedule();
 			remove_wait_queue(&ctl->change_sleep, &wait);
+			if (ctl->card->shutdown)
+				return -ENODEV;
 			if (signal_pending(current))
 				return -ERESTARTSYS;
 			spin_lock_irq(&ctl->read_lock);