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.
There can be other descriptors between the config descriptor and the
first interface descriptor, so we specifically need to check for
the interface descriptor type and skip anything before that.
We also need to guard against bLength == 0, which would cause an
infinite loop, instead of doing a second bDescriptorType check.
