commit 1eaf35e4 upstream.

The module should fail to load.
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ luis: backported to 3.16:
  - moved usb_disabled() check to the top of the function so that there's
    no need to invoke xhci_unregister_pci() before returning.  Suggested
    by gregkh. ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>