usb: core: rename mutex usb_bus_list_lock to usb_bus_idr_lock

Now that usb_bus_list has been removed and switched to idr
rename the related mutex accordingly.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index c293dd0..b98f831 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -632,7 +632,7 @@
 /* exported only within usbcore */
 
 extern struct idr usb_bus_idr;
-extern struct mutex usb_bus_list_lock;
+extern struct mutex usb_bus_idr_lock;
 extern wait_queue_head_t usb_kill_urb_queue;