USB: remove use of the bus rwsem, as it doesn't really protect anything.

The driver core stopped using the rwsem a long time ago, yet the USB
core still grabbed the lock, thinking it protected something.  This
patch removes that useless use.

Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oneukum@suse.de>
Cc: David Brownell <david-b@pacbell.net>
Cc: linux-usb-devel <linux-usb-devel@lists.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 9e3e943..e6dd2b9 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -287,9 +287,9 @@
  * way to bind to an interface is to return the private data from
  * the driver's probe() method.
  *
- * Callers must own the device lock and the driver model's usb_bus_type.subsys
- * writelock.  So driver probe() entries don't need extra locking,
- * but other call contexts may need to explicitly claim those locks.
+ * Callers must own the device lock, so driver probe() entries don't need
+ * extra locking, but other call contexts may need to explicitly claim that
+ * lock.
  */
 int usb_driver_claim_interface(struct usb_driver *driver,
 				struct usb_interface *iface, void* priv)
@@ -330,9 +330,9 @@
  * also causes the driver disconnect() method to be called.
  *
  * This call is synchronous, and may not be used in an interrupt context.
- * Callers must own the device lock and the driver model's usb_bus_type.subsys
- * writelock.  So driver disconnect() entries don't need extra locking,
- * but other call contexts may need to explicitly claim those locks.
+ * Callers must own the device lock, so driver disconnect() entries don't
+ * need extra locking, but other call contexts may need to explicitly claim
+ * that lock.
  */
 void usb_driver_release_interface(struct usb_driver *driver,
 					struct usb_interface *iface)