[USBPORT] Correctly handle alternate settings returned from USBPORT_ParseConfiguratio...

[USBPORT] Correctly handle alternate settings returned from USBPORT_ParseConfigurationDescriptor.

The last parameter of USBPORT_ParseConfigurationDescriptor is a pointer
to a boolean indicating whether any alternate interface settings were
found for the specified interface.
Interpreting it as an alternate setting value, as we did before,
would always override the alternate setting to '1' (if any alternate
descriptors were present), therefore selecting the wrong interface
setting, and possibly causing a buffer overflow on the InterfaceList's
Pipes array.

Found by Special Pool.