USB: fix failure path in usb_add_hcd()

This patch (as1389) fixes some errors in the failure pathway of
usb_add_hcd().  The actions it takes ought to be exactly the same as
those taken by usb_remove_hcd(), but they aren't.

In one case (removal of the usb_bus_attr_group), the two routines are
brought into agreement by changing usb_remove_hcd().  All the other
discrepancies are fixed by changing usb_add_hcd().

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