[PATCH] usbcore: register root hub in usb_add_hcd

This patch makes usbcore automatically allocate and register the root hub
device for a new host controller when the controller is registered.  This
way the HCDs don't all have to include the same boilerplate code.  As a
pleasant side benefit, the register_root_hub routine can now be made
static and not EXPORTed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>