[ALSA] snd_usb_caiaq: fix potential lockups locking

This patch fixes potential lockups in snd_usb_caiaq by refining the
locking mechanims and by using usb_kill_urb() in favor to
usb_unlink_urb().

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/caiaq/caiaq-device.c b/sound/usb/caiaq/caiaq-device.c
index 7c44a2c..73c08b4 100644
--- a/sound/usb/caiaq/caiaq-device.c
+++ b/sound/usb/caiaq/caiaq-device.c
@@ -42,7 +42,7 @@
 #endif
 
 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
-MODULE_DESCRIPTION("caiaq USB audio, version 1.3.2");
+MODULE_DESCRIPTION("caiaq USB audio, version 1.3.4");
 MODULE_LICENSE("GPL");
 MODULE_SUPPORTED_DEVICE("{{Native Instruments, RigKontrol2},"
 			 "{Native Instruments, RigKontrol3},"
@@ -456,7 +456,7 @@
 	struct snd_usb_caiaqdev *dev;
 	struct snd_card *card = dev_get_drvdata(&intf->dev);
 
-	debug("snd_disconnect(%p)\n", intf);
+	debug("%s(%p)\n", __func__, intf);
 
 	if (!card)
 		return;