[PATCH] usb: drivers/usb/core/devio.c dereferences a userspace pointer

See http://bugzilla.kernel.org/show_bug.cgi?id=6617

.

This function dereference a __user pointer.

Signed-off-by: Philippe Retornaz <couriousous@mandriva.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>