Staging: line6: fix bus_id usage

bus_id is now gone in the linux-next tree, so replace it with dev_name()
so the code works properly.

Cc: Markus Grabner <grabner@icg.tugraz.at>
Cc: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/line6/audio.c

@@ -36,7 +36,8 @@ int line6_init_audio(struct usb_line6 *line6)
 
 	strcpy(card->driver, DRIVER_NAME);
 	strcpy(card->shortname, "Line6-USB");
-	sprintf(card->longname, "Line6 %s at USB %s", line6->properties->name, line6->ifcdev->bus_id);  /* 80 chars - see asound.h */
+	sprintf(card->longname, "Line6 %s at USB %s", line6->properties->name,
+		dev_name(line6->ifcdev));  /* 80 chars - see asound.h */
 	return 0;
 }